CS5490 Two Channel Energy Measurement IC Features & Description Description • The CS5490 is a high-accuracy, two-channel, energy measurement analog front end. • • • • • Superior Analog Performance with Ultra-low Noise Level & High SNR Energy Measurement Accuracy of 0.1% over a 4000:1 Dynamic Range Two Independent 24-bit, 4th-order, Delta-Sigma Modulators for Voltage and Current Measurements Configurable Digital Output for Energy Pulses, Interrupt, zero-crossing, and Energy Direction Supports Shunt Resistor, CT, and Rogowski Coil Current Sensors On-chip Measurements/Calculations: - • • • • • • • • • • • The CS5490 incorporates independent 4th order Delta-Sigma analog-to-digital converters for both channels, reference circuitry, and the proven EXL signal processing core to provide active, reactive, and apparent energy measurement. In addition, RMS and power factor calculations are available. Calculations are output via a configurable energy pulse, or direct UART serial access to on-chip registers. Instantaneous current, voltage, and power measurements are also available over the serial port. The two-wire UART minimizes the cost of isolation where required. Active, Reactive, and Apparent Power RMS Voltage and Current Power Factor and Line Frequency Instantaneous Voltage, Current, and Power A configurable digital output provides energy pulses, zero-crossing, energy direction, or interrupt functions. Interrupts can be generated for a variety of conditions including voltage sag or swell, overcurrent, and more. On-chip register integrity is assured via checksum and write protection. The CS5490 is designed to interface to a variety of voltage and current sensors, including shunt resistors, current transformers, and Rogowski coils. Overcurrent, Voltage Sag, and Voltage Swell Detection Ultra-fast On-chip Digital Calibration Configurable No-load Threshold for Anti-creep Internal Register Protection via Checksum and Write Protection UART Serial Interface On-chip Temperature Sensor On-chip Voltage Reference (25ppm/°C Typ.) Single 3.3 V Power Supply Ultra-fine Phase Compensation Low Power Consumption: <13 mW Power Supply Configurations: On-chip functionality makes digital calibration simple and ultra fast to minimize the time required at the end of the customer production line. Performance across temperature is ensured with an on-chip voltage reference with low drift. A single 3.3V power supply is required, and power consumption is low at <13mW. To minimize space requirements, the CS5490 is offered in a low-cost 16-pin SOIC package. ORDERING INFORMATION - GNDA = 0 V, VDDA: +3.3 V • See Page 56. Low-cost 16-pin SOIC Package VDDA VDDD RESET CS5490 IIN+ IIN- PGA 4th Order Modulator Digital Filter HPF Option UART Serial Interface VIN+ VIN- VREF+ VREF- 10x Voltage Reference 4th Order Modulator Cirrus Logic, Inc. http://www.cirrus.com HPF Option TX Calculation Configurable Digital Output Temperature Sensor System Clock GNDA Digital Filter RX DO Clock Generator XIN XOUT Copyright Cirrus Logic, Inc. 2012 (All Rights Reserved) MODE JUN’12 DS982F2 CS5490 TABLE OF CONTENTS 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 2. Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1 Analog Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1.1 Voltage Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1.2 Current Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1.3 Voltage Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.1.4 Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2 Digital Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.1 Reset Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.2 Digital Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.3 UART Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.3.1 UART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.4 MODE Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 3. Characteristics & Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 4. Signal Flow Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.1 Analog-to-Digital Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.2 Decimation Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.3 IIR Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.4 Phase Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.5 DC Offset & Gain Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 4.6 High-pass & Phase Matching Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.7 Digital Integrators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.8 Low-rate Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.8.1 Fixed Number of Samples Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.8.2 Line-cycle Synchronized Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 4.8.3 RMS Current & Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.8.4 Active Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.8.5 Reactive Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.8.6 Apparent Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.8.7 Peak Voltage & Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.8.8 Power Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.9 Average Active Power Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.10 Average Reactive Power Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 5. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.1 Power-on Reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.2 Power Saving Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.3 Zero-crossing Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.4 Line Frequency Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.5 Energy Pulse Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.5.1 Pulse Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 5.5.2 Pulse Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.6 Voltage Sag, Voltage Swell, and Overcurrent Detection . . . . . . . . . . . . . . . . . . . . .21 5.7 Phase Sequence Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.8 Temperature Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2 DS982F2 CS5490 5.9 Anti-creep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.10 Register Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.10.1 Write Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.10.2 Register Checksum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 6. Host Commands and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1 Host Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1.1 Memory Access Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1.1.1 Page Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1.1.2 Register Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1.1.3 Register Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1.2 Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1.3 Checksum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.1.4 Serial Time Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.2 Hardware Registers Summary (Page 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 6.3 Software Registers Summary (Page 16) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 6.4 Software Registers Summary (Page 17) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.5 Software Registers Summary (Page 18) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6.6 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 7. System Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.1 Calibration in General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.1.1 Offset Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.1.1.1 DC Offset Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.1.1.2 AC Offset Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.1.2 Gain Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 7.1.3 Calibration Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 7.2 Phase Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 7.3 Temperature Sensor Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 7.3.1 Temperature Offset and Gain Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 8. Basic Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 9. Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 10. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 11. Environmental, Manufacturing, & Handling Information . . . . . . . . . . . . . . . . . . . . . . . 56 12. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 DS982F2 3 CS5490 LIST OF FIGURES Figure 1. Oscillator Connections................................................................................................... 7 Figure 2. UART Serial Frame Format ........................................................................................... 7 Figure 3. Active Energy Load Performance.................................................................................. 8 Figure 4. Reactive Energy Load Performance.............................................................................. 9 Figure 5. IRMS Load Performance ............................................................................................... 9 Figure 6. Signal Flow for V, I, P, and Q Measurements ............................................................. 15 Figure 7. Low-rate Calculations .................................................................................................. 16 Figure 8. Power-on Reset Timing ............................................................................................... 18 Figure 9. Zero-crossing Level and Zero-crossing Output on DO ................................................ 19 Figure 10. Energy Pulse Generation and Digital Output Control ................................................ 20 Figure 11. Sag, Swell, & Overcurrent Detect.............................................................................. 21 Figure 12. Phase Sequence A, B, C for Rising Edge Transition ................................................ 22 Figure 13. Phase Sequence C, B, A for Rising Edge Transition ................................................ 23 Figure 14. Byte Sequence for Page Select................................................................................. 24 Figure 15. Byte Sequence for Register Read ............................................................................ 24 Figure 16. Byte Sequence for Register Write ............................................................................. 24 Figure 17. Byte Sequence for Instructions.................................................................................. 24 Figure 18. Byte Sequence for Checksum ................................................................................... 25 Figure 19. Calibration Data Flow ................................................................................................ 51 Figure 20. T Register vs. Force Temp ........................................................................................ 53 Figure 21. Typical Connection Diagram (Single-phase, Two-wire, Power Meter) ...................... 54 LIST OF TABLES Table 1. POR Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Table 2. Command Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Table 3. Instruction Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4 DS982F2 CS5490 1. OVERVIEW The CS5490 is a CMOS power measurement integrated circuit that uses two analog-to-digital converters to measure line voltage and current. The CS5490 calculates active, reactive, and apparent power as well as RMS voltage and current and peak voltage and current. It handles other system-related functions, such as energy pulse generation, voltage sag and swell, overcurrent and zero-crossing detection, and line frequency measurement. A separate analog-to-digital converter is used for on-chip temperature measurement. The CS5490 is optimized to interface to current transformers, shunt resistors, or Rogowski coils for current measurement, and to resistive dividers or voltage transformers for voltage measurement. Two full-scale ranges are provided on the current input to accommodate different types of current sensors. The CS5490’s two differential inputs have a common-mode input range from analog ground (GNDA) to the positive analog supply (VDDA). An on-chip voltage reference (typically 2.4 volts) is generated and provided at analog output, VREF±. The digital output (DO) provides a variety of output signals and, depending on the mode selected, provides energy pulses, zero-crossings, or other choices. The CS5490 includes a UART serial host interface to an external microcontroller. The UART signals include serial data input (RX) and serial data output (TX). DS982F2 5 CS5490 2. PIN DESCRIPTION XOUT XIN RESET IINIIN+ VIN+ VINVREF- 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VDDD MODE RX TX DO VDDA GNDA VREF+ Clock Generator Crystal In Crystal Out 2,1 XIN, XOUT — Connect to an external quartz crystal. Alternatively, an external clock can be supplied to the XIN pin to provide the system clock for the device. Control Pins and Serial Data I/O Digital Output 12 Reset 3 Serial Interface Operating Mode Select 13,14 DO — Configurable digital output for energy pulses, interrupt, energy direction, and zero-crossings. RESET — An active-low Schmitt-trigger input used to reset the chip. TX, RX — UART serial data output/input. 15 MODE — Connect to VDDA for proper operation. Voltage Input 6,7 VIN+, VIN- — Differential analog input for the voltage channel. Current Input 5,4 IIN+, IIN- — Differential analog input for the current channel. Voltage Reference Input 9,8 VREF+, VREF- — The voltage reference output and return. 16 VDDD — Decoupling pin for the internal digital supply. Positive Analog Supply 11 VDDA — The positive analog supply. Analog Ground 10 GNDA — Analog ground. Analog Inputs/Outputs Power Supply Connections Internal Digital Supply 2.1 Analog Pins 2.1.2 Current Input The CS5490 has two differential inputs, one for voltage (VIN) and one for currentIIN). The CS5490 also has two voltage reference pins (VREF) between which a 0.1µ bypass capacitor must be placed. The output of the current-sensing shunt resistor or transformer is connected to the IIN input pins of the CS5490. To accommodate different current-sensing elements, the current channel incorporates a programmable gain amplifier (PGA) with two selectable input gains, as described in the Config0 register description 6.6.1 Configuration 0 (Config0) – Page 0, Address 0 on page 31. There is a 10x gain setting and a 50x gain setting. The full-scale signal level for the current channel is ±50mV and ±250mV for 50x and 10x gain settings, respectively. If the input signal is a sine wave, the maximum RMS voltage is 35.35 mVRMS or 176.78mVRMS, which is approximately 70.7% of maximum peak voltage. 2.1.1 Voltage Input The output of the line voltage resistive divider or transformer is connected to the VIN input of the CS5490. The voltage channel is equipped with a 10x, fixed-gain amplifier. The full-scale signal level that can be applied to the voltage channel is ±250 mV. If the input signal is a sine wave, the maximum RMS voltage is 250mVp / 2 176.78mVRMS, which is approximately 70.7% of maximum peak voltage. 6 DS982F2 CS5490 2.1.3 Voltage Reference 2.2.2 Digital Output The CS5490 generates a stable voltage reference of 2.4V between the VREF pins. The reference system also requires a filter capacitor of at least 0.1µF between the VREF pins. The CS5490 provides a configurable digital output (DO). It can be configured to output energy pulses, interrupt, zero-crossings, or energy directions. Refer to the description of the Config1 register in section 6.6 Register Descriptions on page 31 for more details. The reference system is capable of providing a reference for the CS5490 but has limited ability to drive external circuitry. It is strongly recommended that nothing other than the required filter capacitor is connected to the VREF pins. 2.1.4 Crystal Oscillator An external, 4.096MHz quartz crystal can be connected to the XIN and XOUT pins as shown in Figure 1. To reduce system cost, each pin is supplied with an on-chip load capacitor. XIN XOUT 2.2.3 UART Serial Interface The CS5490 provides two pins, RX and TX, for communication between a host microcontroller and the CS5490. 2.2.3.1 UART The CS5490 provides a two-wire, asynchronous, full-duplex UART port. The CS5490 UART operates in 8-bit mode, which transmits a total of 10 bits per byte. Data is transmitted and received LSB first, with one start bit, eight data bits, and one stop bit. IDLE START 0 1 2 3 4 5 6 7 STOP IDLE DATA C1 = 22pF Figure 2. UART Serial Frame Format The baud rate is defined in the SerialCtrl register. After chip reset, the default baud rate is 600, if MCLK is 4.096MHz. The baud rate is based on the contents of bits BR[15:0] in the SerialCtrl register and is calculated as follows: C2 = 22pF Figure 1. Oscillator Connections Alternatively, an external connected to the XIN pin. clock source can be 2.2 Digital Pins 2.2.1 Reset Input The active-low RESET pin, when asserted for longer than 120µs, will halt all CS5490 operations and reset internal hardware registers and states. When de-asserted, an initialization sequence begins, setting the default register values. To prevent erroneous, noise-induced resets to the part, an external pull-up resistor and a decoupling capacitor are necessary on the RESET pin. DS982F2 BR[15:0] = Baud Rate x (524288/MCLK) or Baud Rate = BR[15:0] / (524288/MCLK) The maximum baud rate is 512K if MCLK is 4.096MHz. The UART has two signals: TX and RX. TX is the serial data output from the CS5490; RX is the serial data input to the CS5490. 2.2.4 MODE Pin The MODE pin must be tied to VDDA for normal operation. The MODE pin is used primarily for factory test procedures. 7 CS5490 3. CHARACTERISTICS & SPECIFICATIONS RECOMMENDED OPERATING CONDITIONS Parameter Positive Analog Power Supply Specified Temperature Range Symbol VDDA TA Min 3.0 -40 Typ 3.3 - Max 3.6 +85 Unit V °C POWER MEASUREMENT CHARACTERISTICS Parameter Active Energy (Note 1 & 2) Reactive Energy (Note 1 & 2) Apparent Power (Note 1 & 3) Current RMS (Note 1, 3, & 4) Symbol Min Typ Max Unit All Gain Ranges Current Channel Input Signal Dynamic Range 4000:1 PAvg - ±0.1 - % All Gain Ranges Current Channel Input Signal Dynamic Range 4000:1 QAvg - ±0.1 - % All Gain Ranges Current Channel Input Signal Dynamic Range 1000:1 S - ±0.1 - % All Gain Ranges Current Channel Input Signal Dynamic Range 1000:1 IRMS - ±0.1 - % Voltage Channel Input Signal Dynamic Range 20:1 VRMS - ±0.1 - % PF - ±0.1 - % Voltage RMS (Note 1 & 3) Power Factor (Note 1 & 3) All Gain Ranges Current Channel Input Signal Dynamic Range 1000:1 Notes: 1. Specifications guaranteed by design and characterization. 2. Active energy is tested with power factor PF = 1.0. Reactive energy is tested with Sin() = 1.0. Energy error measured at system level using single energy pulse. Where: 1) One energy pulse = 0.5Wh or 0.5Varh; 2) VDDA = +3.3V, TA = 25°C, MCLK = 4.096MHz; 3) System is calibrated. 3. Calculated using register values; N ≥ 4000. 4. IRMS error calculated using register values. 1) VDDA = +3.3V; TA = 25°C; MCLK = 4.096MHz; 2) AC offset calibration applied. TYPICAL LOAD PERFORMANCE • • • Energy error measured at system level using single energy pulse; where 1 energy pulse = 0.5Wh or 0.5Varh. IRMS error calculated using register values VDDA = +3.3V; TA = 25°C; MCLK = 4.096MHz 1 Percent Error (%) 0.5 0 Lagging PF = 0.5 Leading PF = 0.5 PF = 1 -0.5 -1 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Current Dynamic Range (x : 1) Figure 3. Active Energy Load Performance 8 DS982F2 CS5490 1 Percent Error (%) 0.5 0 Lagging sin(੮) = 0.5 Leading sin(੮) = 0.5 sin(੮) = 1 -0.5 -1 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Current Dynamic Range (x : 1) Figure 4. Reactive Energy Load Performance 1 Percent Error (%) 0.5 0 IRMS Error IRMS Error -0.5 -1 0 500 1000 1500 Current Dynamic range (x : 1) Figure 5. IRMS Load Performance DS982F2 9 CS5490 ANALOG CHARACTERISTICS • • • • Min/Max characteristics and specifications are guaranteed over all Recommended Operating Conditions. Typical characteristics and specifications are measured at nominal supply voltages and TA = 25°C. VDDA = +3.3V ±10%; GNDA = 0V. All voltages with respect to 0V. MCLK = 4.096MHz. Parameter Symbol Min Typ Max Unit CMRR 80 - - dB -0.25 - VDDA V Analog Inputs (Current Channels) Common Mode Rejection (DC, 50, 60Hz) Common Mode+Signal Differential Full-scale Input Range [(IIN+) – (IIN-)] (Gain = 10) (Gain = 50) IIN - 250 50 - mVP mVP Total Harmonic Distortion (Gain = 50) THD 90 100 - dB Signal-to-Noise Ratio (SNR) (Gain = 10) SNR - 80 80 - dB dB - -115 - dB (Gain = 50) Crosstalk from Voltage Inputs at Full Scale (50, 60Hz) Crosstalk from Current Input at Full Scale (50, 60Hz) - -115 - dB Input Capacitance IC - 27 - pF Effective Input Impedance EII 30 - - k Offset Drift (Without the High-pass Filter) OD - 4.0 - µV/°C - 9 2.2 - µVRMS µVRMS Noise (Referred to Input) (Gain = 10) (Gain = 50) NI Power Supply Rejection Ratio (60Hz) (Gain = 10) (Gain = 50) PSRR 60 68 65 75 - dB dB (DC, 50, 60Hz) CMRR 80 - - dB -0.25 - VDDA V [(VIN+) – (VIN-)] VIN - 250 - mVP Total Harmonic Distortion THD 80 88 - dB Signal-to-Noise Ratio (SNR) SNR - 73 - dB - -115 - dB IC - 2.0 - pF Effective Input Impedance EII 2 - - M Noise (Referred to Input) NV - 40 - µVRMS OD - 16.0 - µV/°C PSRR 60 65 - dB T - ±5 - °C (Note 7) Analog Inputs (Voltage Channels) Common Mode Rejection Common Mode+Signal Differential Full-scale Input Range Crosstalk from Current Inputs at Full Scale (50, 60Hz) Input Capacitance Offset Drift (Without the High-pass Filter) Power Supply Rejection Ratio (Note 7) (60Hz) (Gain = 10) Temperature Temperature Accuracy 10 (Note 6) DS982F2 CS5490 Parameter Symbol Min Typ Max Unit PSCA - 3.9 - mA PC - 12.9 4.5 - mW mW Power Supplies Power Supply Currents (Active State) IA+ (VDDA = +3.3V) Power Consumption (Note 5) Notes: Active State (VDDA = +3.3V) Stand-by State 5. 6. 7. All outputs unloaded. All inputs CMOS level. Temperature accuracy measured after calibration is performed. Measurement method for PSRR: VDDA = +3.3V, a 150mV (zero-to-peak) (60Hz) sinewave is imposed onto the +3.3V DC supply voltage at the VDDA pin. The “+” and “-” input pins of both input channels are shorted to GNDA. The CS5490 is then commanded to continuous conversion acquisition mode, and digital output data is collected for the channel under test. The (zero-to-peak) value of the digital sinusoidal output signal is determined, and this value is converted into the (zero-to-peak) value of the sinusoidal voltage (measured in mV) that would need to be applied at the channel’s inputs, in order to cause the same digital sinusoidal output. This voltage is then defined as Veq PSRR is (in dB): 150 PSRR = 20 log ----------V eq VOLTAGE REFERENCE Parameter Reference Symbol Min Typ Max Unit VREF +2.3 +2.4 +2.5 V (Note 9) TCVREF - 25 - ppm/°C (Note 10) VR - 30 - mV (Note 8) Output Voltage Temperature Coefficient Load Regulation Notes: 8. It is strongly recommended that no connection other than the required filter capacitor be made to VREF±. 9. The voltage at VREF± is measured across the temperature range. From these measurements the following formula is used to calculate the VREF temperature coefficient: VREF MAX – VREFMIN 1 TC VREF = ------------------------------------------------------------ ---------------------------------------------- 1.0 10 6 VREF AVG T A MAX – T A MIN 10. DS982F2 Specified at maximum recommended output of 1µA sourcing. VREF is a very sensitive signal, the output of the VREF circuit has a very high output impedance so that the 0.1µF reference capacitor provides attenuation even to low frequency noise, such as 50Hz noise on the VREF output. As such VREF intended for the CS5490 only and should not be connected to any external circuitry. The output impedance is sufficiently high that standard digital multi-meters can significantly load this voltage. The accuracy of the metrology IC can not be guaranteed when a multimeter or any component other than the 0.1µF capacitor is attached to VREF. If it is desired to measure VREF for any reason other than a very course indicator of VREF functionality, Cirrus recommends a very high input impedance multimeter such as the Keithley Model 2000 Digital Multimeter be used, but still cannot guarantee the accuracy of the metrology with this meter connected to VREF. 11 CS5490 DIGITAL CHARACTERISTICS • • • • Min / Max characteristics and specifications are guaranteed over all Recommended Operating Conditions. Typical characteristics and specifications are measured at nominal supply voltages and TA = 25°C. VDDA = +3.3V ±10%; GNDA = 0V. All voltages with respect to 0V. MCLK = 4.096MHz. Parameter Master Clock Characteristics XIN Clock Frequency XIN Clock Duty Cycle Filter Characteristics Phase Compensation Range Input Sampling Rate Digital Filter Output Word Rate High-pass Filter Corner Frequency Input/Output Characteristics High-level Input Voltage (All Pins) Internal Gate Oscillator Symbol Min Typ Max Unit MCLK 2.5 40 4.096 - 5 60 MHz % -10.79 - MCLK/8 MCLK/1024 2.0 +10.79 - ° Hz Hz Hz VIH 0.6(VDDA) - - V VIL - - 0.6 V ±1 0.5 0.5 ±10 V V V V µA (60Hz, OWR = 4000Hz) (Both channels) OWR -3dB Low-level Input Voltage (All Pins) Input Leakage Current Iin VDDA-0.3 VDDA-0.3 - 3-state Leakage Current IOZ - - ±10 µA Digital Output Pin Capacitance Cout - 5 - pF High-level Output Voltage (Note 12) Low-level Output Voltage (Note 12) Notes: 12 DO, Iout = +10mA Iout = +5mA VOH DO, Iout = -12mA All Other Outputs, Iout = -5mA VOL 11. All measurements performed under static conditions. 12. XOUT pin used for crystal only. Typical drive current<1mA. DS982F2 CS5490 SWITCHING CHARACTERISTICS • • • • Min / Max characteristics and specifications are guaranteed over all Recommended Operating Conditions. Typical characteristics and specifications are measured at nominal supply voltages and TA = 25°C. VDDA = +3.3V ±10%; GNDA = 0V. All voltages with respect to 0V. Logic Levels: Logic 0 = 0V, Logic 1 = VDDA. Parameter Rise Times (Note 13) Fall Times (Note 13) Symbol Min Typ Max Unit DO Any Digital Output Except DO trise - 50 1.0 - µs ns DO Any Digital Output Except DO tfall - 50 1.0 - µs ns XTAL = 4.096 MHz (Note 14) tost - 60 - ms Start-up Oscillator Start-up Time Notes: 13. Specified using 10% and 90% points on waveform of interest. Output loaded with 50pF. 14. Oscillator start-up time varies with crystal parameters. This specification does not apply when using an external clock source. DS982F2 13 CS5490 ABSOLUTE MAXIMUM RATINGS Parameter DC Power Supplies Input Current (Note 15) (Notes 16 and 17) Input Current for Power Supplies Symbol Min Typ Max Unit VDDA -0.3 - +4.0 V IIN - - ±10 mA - - - ±50 - Output Current (Note 18) IOUT - - 100 mA Power Dissipation (Note 19) PD - - 500 mW Input Voltage (Note 20) VIN - 0.3 - (VDDA) + 0.3 V 2 Layer Board 4 Layer Board JA - 140 70 - °C/W °C/W Ambient Operating Temperature TA - 40 - 85 °C Storage Temperature Tstg - 65 - 150 °C Junction-to-Ambient Thermal Impedance Notes: 15. VDDA and GNDA must satisfy [(VDDA) – (GNDA)] + 4.0V. 16. Applies to all pins, including continuous overvoltage conditions at the analog input pins. 17. Transient current of up to 100mA will not cause SCR latch-up. 18. Applies to all pins, except VREF±. 19. Total power dissipation, including all input currents and output currents. 20. Applies to all pins. WARNING: Operation at or beyond these limits may result in permanent damage to the device. Normal operation is not guaranteed at these extremes. 14 DS982F2 VIN± PMF 4th Order ∆Σ Modulator x10 MUX CS5490 DELAY CTRL IIR SINC3 V HPF Phase Shift PC ... CPCC[1:0] ... FPCC[8:0] ... SYS GAIN Config 2 I DCOFF IIN± 4th Order ∆Σ Modulator PGA DELAY CTRL SINC3 VGAIN IIR Epsilon ... VFLT[1:0] IFLT[1:0] ... 2 P I GAIN HPF INT PMF MUX VDCOFF Q I Registers Figure 6. Signal Flow for V, I, P, and Q Measurements 4. SIGNAL FLOW DESCRIPTION The signal flow for voltage, current measurement, and the other calculations is shown in Figure 6. The signal flow consists of a current and a voltage channel. The current and voltage channels have differential input pins. 4.1 Analog-to-Digital Converters Both input channels use fourth-order delta-sigma modulators to convert the analog inputs to single-bit digital data streams. The converters sample at a rate of MCLK/8. This high sampling provides a wide dynamic range and simplifies anti-alias filter design. 4.2 Decimation Filters The single-bit modulator output data is widened to 24 bits and down sampled to MCLK/1024 with low-pass decimation filters. These decimation filters are third-order Sinc filters. The filter outputs pass through an IIR "anti-sinc" filter. 4.3 IIR Filter The IIR filter is used to compensate for the amplitude roll-off of the decimation filters. The droop-correction filter flattens the magnitude response of the channel out to the Nyquist frequency, thus allowing for accurate measurements of up to 2kHz (MCLK = 4.096MHz). By default, the IIR filters are enabled. The IIR filters can be bypassed by setting the IIR_OFF bit in the Config2 register. DS982F2 4.4 Phase Compensation Phase compensation changes the phase of voltage relative to current by adding a delay in the decimation filters. The amount of phase shift is set by the PC register bits CPCC[1:0] and FPCC[8:0] for the current channel. For the voltage channel, only bits CPCC[1:0] affect the delay. Fine phase compensation control bits, FPCC[8:0], provide up to 1/OWR delay in the current channel. Coarse phase compensation control bits, CPCC[1:0], provide an additional 1/OWR delay in the current channel or up to 2/OWR delay in the voltage channel. Negative delay in the voltage channel can be implemented by setting longer delay in the current channel than the voltage channel. For a OWR of 4000Hz, the delay range is ±500µs, a phase shift of ±8.99° at 50Hz and ±10.79° at 60Hz. The step size is 0.008789° at 50Hz and 0.010547° at 60Hz. For more information about phase compensation, see section 7.2 Phase Compensation on page 52. 4.5 DC Offset & Gain Correction The system and CS5490 inherently have component tolerances, gain, and offset errors, which can be removed using the gain and offset registers. Each measurement channel has its own set of gain and offset registers. For every instantaneous voltage and current sample, the offset and gain values are used to correct DC offset and gain errors in the channel (see section 7. System Calibration on page 51 for more details). 15 CS5490 4.6 High-pass & Phase Matching Filters Optional high-pass filters (HPF in Figure 6) remove any DC component from the selected signal paths. Each power calculation contains a current and voltage channel. If an HPF is enabled in only one channel, a phase-matching filter (PMF) should be applied to the other channel to match the phase response of the HPF. For AC power measurement, high-pass filters should be enabled on the voltage and current channels. For information about how to enable and disable the HPF or PMF on each channel, refer to Config2 register descriptions in section 6.6 Register Descriptions on page 31. 4.7 Digital Integrators Optional digital integrators (INT in Figure 6) are implemented on the current channel to compensate for the 90° phase shift and 20dB/decade gain generated by the Rogowski coil current sensor. When a Rogowski coil is used as the current sensor, the integrator (INT) should be enabled on that current channel. For information about how to enable and disable the INT on the current channel, refer to Config2 register descriptions in section 6.6 Register Descriptions on page 31. 4.8 Low-rate Calculations All the RMS and power results come from low-rate calculations by averaging the output word rate (OWR) instantaneous values over N samples, where N is the value stored in the SampleCount register. The low-rate interval or averaging period is N divided by OWR (4000Hz if MCLK = 4.096MHz). The CS5490 provides N V ÷N two averaging modes for low-rate calculations: Fixed Number of Sample Averaging mode and Line-cycle Synchronized Averaging mode. By default, the CS5490 averages with the Fixed Number of Samples Averaging mode. By setting the AVG_MODE bit in the Config2 register, the CS5490 will use the Line-cycle Synchronized Averaging mode. 4.8.1 Fixed Number of Samples Averaging N is the preset value in the SampleCount register and should not be set less than 100. By default, the SampleCount register is 4000. With MCLK = 4.096 MHz, the averaging period is fixed at N/4000 = 1 second, regardless of the line frequency. 4.8.2 Line-cycle Synchronized Averaging When operating in Line-cycle Synchronized Averaging mode, and when line frequency measurement is enabled (see section 5.4 Line Frequency Measurement on page 19), the CS5490 uses the voltage (V) channel zero crossings and measured line frequency to automatically adjust N such that the averaging period will be equal to the number of half line-cycles in the CycleCount register. For example, if the line frequency is 51Hz, and the CycleCount register is set to 100, N will be 4000 (100/2)/51 = 3921 during continuous conversion. N is self-adjusted according to the line frequency, therefore the averaging period is always close to the whole number of half line-cycles, and the low-rate calculation results will minimize ripple and maximize resolution, especially when the line frequency varies. Before starting a low-rate conversion in the Line-cycle Synchronized Averaging mode, the V RMS Config 2 ... APCM ... I ACOFF ÷N + - IRMS MUX N I QOFF N Q ÷N + + QAVG X POFF N P S ÷N + + Inverse PAVG X Registers + + X PF Figure 7. Low-rate Calculations 16 DS982F2 CS5490 SampleCount register should not be changed from its default value of 4000, and bit AFC of the Config2 register must be set. During continuous conversion, the host processor should not change the SampleCount register. 4.8.3 RMS Current & Voltage The root mean square (RMS in Figure 7) calculations are performed on N instantaneous voltage and current samples using Equation 1: The APCM bit in the Config2 register controls which method is used for apparent power calculation. 4.8.7 Peak Voltage & Current Peak current (IPEAK) and peak voltage (VPEAK) are calculated over N samples and recorded in the corresponding channel peak register documented in the register map. This peak value is updated every N samples. 4.8.8 Power Factor Power factor (PF) is active power divided by apparent power, as shown below. The sign of the power factor is determined by the active power. See Equation 4. N–1 I RMS = N–1 I 2n n=0 -------------------N V RMS = V 2n n=0 ---------------------N [Eq.1] The instantaneous voltage and current samples are multiplied to obtain the instantaneous power (P) (see Figure 6). The product is then averaged over N samples to compute active power (PAVG). 4.8.5 Reactive Power Instantaneous reactive power (Q) is the sample rate result obtained by multiplying instantaneous current (I) by instantaneous quadrature voltage (Q). These values are created by phase shifting instantaneous voltage (V) 90° using first-order integrators (see Figure 6). The gain of these integrators is inversely related to line frequency, so their gain is corrected by the Epsilon register, which is based on line frequency. Reactive power (QAVG) is generated by integrating the instantaneous quadrature power over N samples. 4.8.6 Apparent Power By default, the CS5490 calculates the apparent power (S) as the product of RMS voltage and current. See Equation 2: S = V RMS I RMS [Eq.2] The CS5490 also provides an alternate apparent power calculation method. The alternate apparent power method uses real power (PAVG) and reactive power (QAVG) to calculate apparent power. See Equation 3. DS982F2 Q AVG 2 + P AVG 2 [Eq.4] 4.9 Average Active Power Offset 4.8.4 Active Power S = P ACTIVE PF = ---------------------S [Eq.3] The average active power offset register, POFF, can be used to offset erroneous power sources resident in the system not originating from the power line. Residual power offsets are usually caused by crosstalk into the current channel from the voltage channel, or from ripple on the meter’s or chip’s power supply, or from inductance from a nearby transformer. These offsets can be either positive or negative, indicating crosstalk coupling either in phase or out of phase with the applied voltage input. The power offset register can compensate for either condition. To use this feature, measure the average power at no load and take the measured result (from the PAVG register), invert (negate) the value, and write it to the associated power offset register, POFF. 4.10 Average Reactive Power Offset The average reactive power offset register, QOFF, can be used to offset erroneous power sources resident in the system not originating from the power line. Residual reactive power offsets are usually caused by crosstalk into the current channel from the voltage channel, or from ripple on the meter’s or chip’s power supply, or from inductance from a nearby transformer. These offsets can be either positive or negative, depending on the phase angle between the crosstalk coupling and the applied voltage. The reactive power offset register can compensate for either condition. To use this feature, measure the average reactive power at no load. Take the measured result from the QAVG register, invert (negate) the value and write it to the reactive power offset register, QOFF. 17 CS5490 5. FUNCTIONAL DESCRIPTION 5.1 Power-on Reset (POR) Table 1. POR Thresholds The CS5490 has an internal power supply supervisor circuit that monitors the VDDA and VDDD power supplies and provides the master reset to the chip. If any of these voltages are in the reset range, the master reset is triggered. Both the analog and the digital supply have their own POR circuit. During power-up, both supplies have to be above the rising threshold for the master reset to be de-asserted. Each POR is divided into 2 blocks: rough and fine. Rough POR triggers the fine POR. Rough POR depends only on the supply voltage. The trip point for the fine POR is dependent on bandgap voltage for precise control. The POR circuit also acts as a brownout detect. The fine POR detects supply drops and asserts the master reset. The rough and fine PORs have hysteresis in their rise and fall thresholds which prevents the reset signal from chattering. The following plot shows the POR outputs for each of the power supplies. The POR_Fine_VDDA and POR_Fine_VDDD signals are AND-ed to form the actual power-on reset signal to the digital circuity. The digital circuitry, in turn, holds the master reset signal for 130ms and then de-asserts the master reset. VDDA Vth5 Vth2 Vth1 Vth6 POR_Rough_VDDA POR_Fine_VDDA Vth4 VDDD Typical POR Threshold VDDA VDDD Rising Falling Rough Vth1 = 2.34V Vth6 = 2.06V Fine Vth2 = 2.77V Vth5 = 2.59V Rough Vth3 = 1.20V Vth8 = 1.06V Fine Vth4 = 1.51V Vth7 = 1.42V 5.2 Power Saving Modes Power Saving modes for CS5490 are accessed through the Host Instruction Commands (see 6.1 Host Commands on page 24). • Standby: Powers down all the ADCs, rough buffer, and the temperature sensor. Standby mode disables the system time calculations. Use the wake-up command to come out of standby mode. • Wake-up: Clears the ADC power-down bits and starts the system time calculations. After any of these commands are completed, the DRDY bit is set in the Status0 register. 5.3 Zero-crossing Detection Zero-crossing detection logic is implemented in CS5490. A low-pass filter can be enabled by setting ZX_LPF bit in register Config2. The low-pass filter has a cut-off frequency of 80Hz. It is used to eliminate any harmonics and to help the zero-crossing detection on the 50Hz or 60Hz fundamental component. The zero-crossing level registers are used to set the minimum threshold over which the channel peak has to exceed in order for the zero-crossing detection logic to function. There are two separate zero-crossing level registers: VZXLEVEL is the threshold for the voltage channels, and IZXLEVEL is the threshold for the current channels. Vth7 Vth8 Vth3 POR_Rough_VDDD POR_Fine_VDDD POR_Fine_VDDA POR_Fine_VDDD Master Reset 130ms Figure 8. Power-on Reset Timing 18 DS982F2 CS5490 V(t), I(t) If |VPEAK| > VZXLEVEL, then voltage zero-crossing detection is enabled. If |IPEAK| > IZXLEVEL, then current zero-crossing detection is enabled. If |VPEAK| VZXLEVEL, then voltage zero-crossing detection is disabled. If |IPEAK| IZXLEVEL, then current zero-crossing detection is disabled. VZXLEVEL IZXLEVEL t DO Zero-crossing output on DOx pin Pulse width = 250μs t Figure 9. Zero-crossing Level and Zero-crossing Output on DO 5.4 Line Frequency Measurement If the Automatic Frequency Calculation (AFC) bit in the Config2 register is set, the line frequency measurement on the voltage channel will be enabled. The line frequency measurement is based on a number of voltage channel zero crossings. This number is 100 by default and configurable through the ZXNUM register (see section 6.6.56 on page 50). The Epsilon register will be updated automatically with the line frequency information. The Frequency Update (FUP) bit in the Status0 interrupt status register is set when the frequency calculation is completed. When the line frequency is 50Hz and the ZXNUM register is 100, the Epsilon register is updated every one second with a resolution of less than 0.1%. A larger zero-crossing number in the ZXNUM register will increase line frequency measurement resolution and period. Note that the CS5490 line frequency measurement function does not support the line frequency out of the range of 40Hz to 75Hz. DS982F2 The Epsilon register is also used to set the gain of the 90° phase shift filter used in the quadrature power calculation. The value in the Epsilon register is the ratio of the line frequency to the output word rate (OWR). For 50Hz line frequency and 4000Hz OWR, Epsilon is 50/4000 (0.0125) (the default). For 60Hz line frequency, it is 60/4000 (0.015). 5.5 Energy Pulse Generation The CS5490 provides an independent energy pulse generation (EPG) block in order to output active, reactive, and apparent energy pulses on the digital output pin (DO). The energy pulse frequency is proportional to the magnitude of the power. The energy pulse output is commonly used as the test output of a power meter. The host microcontroller can also use the energy pulses to easily accumulate the energy. Refer to Figure 10. 19 CS5490 EPG_ON (Config1) MCLK 0000 P AVG 0010 0011 Q AVG Reserved 0100 Q SUM 0101 S 0110 Reserved S SUM 0111 Energy Pulse Generation (EPG) P SUM 0001 1000 PULSE RATE (PulseCtrl) EPGIN[3:0] 4 (PulseWidth) FREQ_RNG[3:0] 4 (PulseWidth) PW[7:0] 8 Reserved 0001 Reserved 0010 Reserved 0011 P Sign 0100 Reserved 0101 PSUM Sign 0110 Q Sign 0111 Reserved 1000 Q SUM Sign 1001 Reserved 1010 V Crossing 1011 I Crossing 1100 Reserved 1101 Hi-Z 1110 Interrupt 1111 DOMODE[3:0] (Config1) Digital Output Mux (DO) 0000 Reserved DO_OD (Config1) DO 4 Figure 10. Energy Pulse Generation and Digital Output Control After reset, the energy pulse generation block is disabled (DOMODE[3:0] = Hi-Z). To output a desired energy pulse to a DO pin, it is necessary to follow the steps below: 1. Write to register PulseWidth (page 0, address 8) to select the energy pulse width and pulse frequency range. 2. Write to register PulseRate (page 18, address 28) to select the energy pulse rate. 3. Write to register PulseCtrl (page 0, address 9) to select the input to the energy pulse generation block. 4. Write ‘1’ to bit EPG_ON of register Config1 (page 0, address 1) to enable the energy pulse generation block. 5. Wait at least 0.1s. 6. Write bits DOMODE[3:0] of register Config1 to select DO to output pulses from the energy pulse generation block. 7. Send DSP instruction (0xD5) to begin continuous conversion. 20 5.5.1 Pulse Rate Before configuring the PulseRate register, the full-scale pulse rate needs to be calculated, and the frequency range needs to be specified through FREQ_RNG[3:0] bits in the PulseWidth register. For example, if a meter has the meter constant of 1000imp/kWh, a maximum voltage (UMAX) of 240V, and a maximum current (IMAX) of 100A, the maximum pulse rate is: [1000x(240x100/1000)]/3600 = 6.6667Hz. Assume the meter is calibrated with UMAX and IMAX, and the Scale register contains the default value of 0.6. After gain calibration, the power register value will be 0.36, which represents 240 x 100 = 24kW or 6.6667Hz pulse output rate. The full-scale pulse rate is: Fout = 6.6667/0.36 = 18.5185Hz. Refer to section 6.6.6 Pulse Output Width (PulseWidth) – Page 0, Address 8 on page 35. The FREQ_RNG[3:0] bits should be set to b[0110]. DS982F2 CS5490 The CS5490 pulse generation block behaves as follows: • The pulse rate generated by full-scale (1.0 decimal) power register is FOUT = (PulseRate x 2000)/2FREQ_RNG • The PulseRate register value is PulseRate = (FOUT x 2FREQ_RNG)/2000 = (18.5186 x 64)/2000 = 0.5925952 = 0x4BDA29 5.5.2 Pulse Width The PulseWidth register defines the Active-low time of each energy pulse: these to zero (default) disables the detect feature for the given channel. The value is in output word rate (OWR) samples. The predetermined level is set by the values in the VSagLEVEL , VSwellLEVEL , and IOverLEVEL registers. For each enabled input channel, the measured value is rectified and compared to the associated level register. Over the duration window, the number of samples above and below the level are counted. If the number of samples below the level exceeds the number of samples above, a Status0 register bit VSAG is set, indicating a sag condition. If the number of samples above the level exceeds the number of samples below, a Status0 register bit VSWELL or IOVER is set, indicating a swell or overcurrent condition (see Figure 11). Active-low = 250µs + (PulseWidth/64000). By default, the PulseWidth register value is 1, and the Active-low time of each energy pulse is 265.6µs. Note that the pulse width should never exceed the pulse period. 5.6 Voltage Sag, Voltage Swell, and Overcurrent Detection Voltage sag detection is used to determine when the voltage falls below a predetermined level for a specified interval of time (duration). Voltage swell and overcurrent detection determine when the voltage or current rises above a predetermined level for the duration. The duration is set by the value in the VSagDUR , VSwellDUR , and IOverDUR registers. Setting any of DS982F2 L e ve l D u ra tio n Figure 11. Sag, Swell, & Overcurrent Detect 21 CS5490 5.7 Phase Sequence Detection Polyphase meters using multiple CS5490 devices may be configured to sense the succession of voltage zero-crossings and determine which phase order is in service. The phase sequence detection within CS5490 involves counting the number of OWR samples from a starting point to the next voltage zero-crossing rising edge or falling for each phase. By comparing the count for each phase, the phase sequence can be easily determined: the smallest count is first, and the largest count is last. The phase sequence detection and control (PSDC) register provides the count control, zero-crossing direction and count results. Writing '0' to bit DONE and '10110' to bits CODE[4:0] of the PSDC register followed by a falling edge on the RX pin will initiate the phase sequence detection circuit. The RX pin must be held low for a minimum of 500ns. When the device is in UART mode, it is recommended that a 0xFF command be written to all parts to start the phase sequence detection. Multiple CS5490 devices in a polyphase meter must receive the register writing and the RX falling edge at the same time so that all CS5490 devices starts to count simultaneously. Bit DIR of PSDC register specifies the direction of the next zero crossing at which the count stops. If bit DIR is '0', the count stops at the next negative-to-positive zero crossing. If bit DIR is '1', the count stops at the next positive-to-negative zero Write 0x16 to PSDC Register Start on the Falling Edge on the RX Pin 2 crossing. When the count stops, the DONE bit will be set by the CS5490, and then the count result of each phase may be read from bits PSCNT[6:0] of the PSDC register. If the PSCNT[6:0] bits are equal to 0x00, 0x7F or greater than 0x64 (for 50Hz) or 0x50 (for 60Hz), then a measurement error has occurred, and the measurement results should be disregarded. This could happen when the voltage input signal amplitude is lower than the amplitude specified in the VZXLEVEL register. To determine the phase order, the PSCNT[6:0] bit counts from each CS5490 are sorted in ascending order. Figure 12 and Figure 13 illustrate how phase sequence detection is performed. Phase sequences A, B, and C for the default rising edge transition are illustrated in Figure 12. The PSCNT[6:0] bits from the CS5490 on phase A will have the lowest count, followed by the PSCNT[6:0] bits from the CS5490 on phase B with the middle count, and the PSCNT[6:0] bits from the CS5490 on phase C with the highest count. Phase sequences C, B, and A for rising edge transition are illustrated in Figure 13. The PSCNT[6:0] bits from the CS5490 on phase C will have the lowest count, followed by the PSCNT[6:0] bits from the CS5490 on phase B with the middle count, and the PSCNT[6:0] bits from the CS5490 on phase A with the highest count. Phase A Channel Stop Phase A Count 0 -2 A Phase B Channel 2 Stop Phase B Count 0 -2 C B Phase C Channel Stop 2 Phase C Count 0 -2 Figure 12. Phase Sequence A, B, C for Rising Edge Transition 22 DS982F2 CS5490 Write 0x16 to PSDC Register Start on the Falling Edge on the RX Pin Phase A Channel Stop 2 Phase A Count 0 -2 C Phase B Channel Stop 2 Phase B Count 0 -2 A B Phase C Channel Stop 2 Phase C Count 0 -2 Figure 13. Phase Sequence C, B, A for Rising Edge Transition be write-protected from the calculation engine. Setting 5.8 Temperature Measurement the DSP_LCK[4:0] bits to 0x09 disables the The CS5490 has an internal temperature sensor, which write-protection mode. is designed to measure temperature and optionally Setting the HOST_LCK[4:0] bits in the RegLock register compensate for temperature drift of the voltage to 0x16 enables the CS5490 HOST lockable registers to reference. Temperature measurements are stored in be write-protected from the serial interface. Setting the the temperature register (T), which, by default, is HOST_LCK[4:0] bits to 0x09 disables the configured to a range of ±128°C. write-protection mode. The application program can change the scale and For registers that are DSP lockable, HOST lockable, or range of the temperature (T) register by changing the both, refer to sections 6.2 Hardware Registers temperature gain (TGAIN) register and temperature Summary (Page 0) on page 26, 6.3 Software Registers offset (TOFF) register. Summary (Page 16) on page 28, and 6.4 Software The temperature (T) register updates every 2240 output Registers Summary (Page 17) on page 29. word rate (OWR) samples. The Status0 register bit TUP 5.10.2 Register Checksum indicates when T is updated. All the configuration and calibration registers are 5.9 Anti-creep protected by checksum, if enabled. Refer to sections 6.2 The anti-creep (no-load threshold) is used to determine Hardware Registers Summary (Page 0) on page 26, 6.3 if a no-load condition is detected. The |PSum| and |QSum| Software Registers Summary (Page 16) on page 28, are compared to the value in the no-load threshold and 6.4 Software Registers Summary (Page 17) on (LoadMin) register. If both |PSum| and |QSum| are less page 29. The checksum for all registers marked with an than this threshold, then PSum and QSum are forced to asterisk symbol (*) is computed at the rate of OWR. The zero. If SSum is less than the value in LoadMin register, checksum result is stored in the RegChk register. After then SSum is forced to zero. the CS5490 has been fully configured and loaded with the calibrations, the host microcontroller should keep a 5.10 Register Protection copy of the checksum (RegChk_Copy) in its memory. In To prevent the critical configuration and calibration normal operation, the host microcontroller can read the registers from unintended changes, the CS5490 provides RegChk register and compare it with the saved copy of two enhanced register protection mechanisms: write the RegChk register. If the two values mismatch, a reload protection and automatic checksum calculation. of configurations and calibrations into the CS5490 is 5.10.1 Write Protection necessary. Setting the DSP_LCK[4:0] bits in the RegLock register The automatic checksum computation can be disabled by to 0x16 enables the CS5490 DSP lockable registers to setting the REG_CSUM_OFF bit in the Config2 register. DS982F2 23 CS5490 6. HOST COMMANDS AND REGISTERS 6.1 Host Commands 6.1.1.3 Register Write The first byte sent to the CS5490 RX pin contains the host command. Four types of host commands are required to read and write registers and instruct the calculation engine. The two most significant bits (MSBs) of the host command defines the function to be performed. The following table depicts the types of commands. A register write command is designated by setting the two MSBs of the command to binary ‘01’. The lower 6 bits of the register write command are the lower 6 bits of the 12-bit register address. A register write command must be followed by 3 bytes of data. Table 2. Command Format Figure 16. Byte Sequence for Register Write Function Binary Value Note Register Read 0 0 A5 A4 A3 A2 A1 A0 Register Write 0 1 A5 A4 A3 A2 A1 A0 Page Select 1 0 P5 P4 P3 P2 P1 P0 P[5:0] specifies the page. Instruction 1 1 C5 C4 C3 C2 C1 C0 C[5:0] specifies the instruction. A[5:0] specifies the register address. 6.1.1 Memory Access Commands The CS5490 memory has 12-bit addresses and is organized as P5 P4 P3 P2 P1 P0 A5 A4 A3 A2 A1 A0 in 64 pages of 64 addresses each. The higher 6 bits specify the page number. The lower 6 bits specify the address within the selected page. 6.1.1.1 Page Select A page select command is designated by setting the two MSBs of the command to binary ‘10’. The page select command provides the CS5490 with the page number of the register to access. Register read and write commands access 1 of 64 registers within a specified page. Subsequent register reads and writes can be performed once the page has been selected. RX RX RX Instruction Figure 17. Byte Sequence for Instructions These new processes include calibration, power control, and soft reset. The following table depicts the types of instructions. Note that when the CS5490 is in continuous conversion mode, an unexpected or invalid instruction command could cause the device to stop continuous conversion and enter an unexpected operation mode. The host processor should keep monitoring the CS5490 operation status and react accordingly. Table 3. Instruction Format Function Controls TX DATA DATA Binary Value 0 C4 C3 C2 C1 C0 0 00001 - Software Reset 0 00010 - Standby 0 00011 - Wakeup 0 10100 - Single Conv. 0 10101 - Continuous Conv. 0 11000 - Halt Conv. Note C[5] specifies the instruction type: 0 = Controls 1 = Calibrations 1 C4 C3 C2 C1 C0 6.1.1.2 Register Read Read Cmd. DATA An instruction command is designated by setting the two MSBs of the command to binary '11'. An instruction command will interrupt any process currently running and initiate a new process in the CS5490. Figure 14. Byte Sequence for Page Select RX DATA 6.1.2 Instructions Page Select Cmd. A register read is designated by setting the two MSBs of the command to binary ‘00’. The lower 6 bits of the read register command are the lower 6 bits of the 12-bit register address. After the register read command has been received, the CS5490 will send 3 bytes of register data onto the TX pin. DATA Write Cmd. Calibration 1 00 C2C1C0 DC Offset AC Offset* 1 10 C2C1C0 1 11 C2C1C0 Gain *AC offset calibration valid only for current channel. For calibration, C[4:3] specifies the type of calibration. 1 C4 C3 C2 C1 C0 1 C4C3 1 C4C3 1 C4C3 001 010 110 I V I&V For calibration, C[2:0] specifies the channel(s). DATA Figure 15. Byte Sequence for Register Read 24 DS982F2 CS5490 6.1.3 Checksum To improve the communication reliability on the serial interface, the CS5490 provides a checksum mechanism on transmitted and received signals. Checksum is disabled by default but can be enabled by setting the appropriate bit in the SerialCtrl register. When enabled, both host and CS5490 are expected to send one additional checksum byte after the normal command byte and applicable 3-byte register data have been transmitted. RX The checksum is calculated by subtracting each transmit byte from 0xFF. Any overflow is truncated and the result wraps. The CS5490 executes the command only if the checksum transmitted by the host matches the checksum calculated locally. Otherwise, it sets a status bit (RX_CSUM_ERR in Status0 register), ignores the command, and clears the serial interface in preparation for the next transmission. RX DS982F2 Page Select Cmd. Checksum Page Select RX Instruction Checksum Instruction RX Read Cmd. CHECKSUM TX DATA DATA DATA CHECKSUM Read Command Write Cmd. DATA DATA DATA CHECKSUM Write Command Figure 18. Byte Sequence for Checksum 6.1.4 Serial Time Out In case a transaction from the host is not completed (for example, a data byte is missing in a register write), a time out circuit will reset the interface after 128ms. This will require that each byte be sent from the host within 128ms of the previous byte. 25 CS5490 6.2 Hardware Registers Summary (Page 0) Address2 0* 1* 2 3* 4 5* 6 7* 8* 9* 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34* 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 26 RA[5:0] 00 0000 00 0001 00 0010 00 0011 00 0100 00 0101 00 0110 00 0111 00 1000 00 1001 00 1010 00 1011 00 1100 00 1101 00 1110 00 1111 01 0000 01 0001 01 0010 01 0011 01 0100 01 0101 01 0110 01 0111 01 1000 01 1001 01 1010 01 1011 01 1100 01 1101 01 1110 01 1111 10 0000 10 0001 10 0010 10 0011 10 0100 10 0101 10 0110 10 0111 10 1000 10 1001 10 1010 10 1011 10 1100 10 1101 10 1110 10 1111 11 0000 11 0001 11 0010 11 0011 11 0100 Name Config0 Config1 Mask PC SerialCtrl PulseWidth PulseCtrl Status0 Status1 Status2 RegLock VPEAK IPEAK PSDC - Description1 Configuration 0 Configuration 1 Reserved Interrupt Mask Reserved Phase Compensation Control Reserved UART Control Energy Pulse Width Energy Pulse Control Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Interrupt Status Chip Status 1 Chip Status 2 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Register Lock Control Reserved Peak Voltage Peak Current Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Phase Sequence Detection & Control Reserved Reserved Reserved Reserved DSP3 Y Y Y Y Y Y Y N N N N N N N - HOST 3 Default Y 0x C0 2000 Y 0x 00 EEEE Y 0x 00 0000 Y 0x 00 0000 Y 0x 02 004D Y 0x 00 0001 Y 0x 00 0000 N 0x 80 0000 N 0x 80 1800 N 0x 00 0000 N 0x 00 0000 Y 0x 00 0000 Y 0x 00 0000 Y 0x 00 0000 DS982F2 CS5490 53 54 55 56 57 58 59 60 61 62 63 Notes: 11 0101 11 0110 11 0111 11 1000 11 1001 11 1010 11 1011 11 1100 11 1101 11 1110 11 1111 ZXNUM - Reserved Reserved Num. Zero Crosses used for Line Freq. Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Y - Y 0x00 0064 - (1) Warning: Do not write to unpublished or reserved register locations. (2) * Registers with checksum protection. (3) Registers that can be set to write protect from DSP and/or HOST. DS982F2 27 CS5490 6.3 Software Registers Summary (Page 16) Address2 0* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32* 33* 34* 35* 36* 37* 38* 39* 40* 41* 42* 43* 44* 45* 46 47 48 49 50* 51* 52 28 RA[5:0] 00 0000 00 0001 00 0010 00 0011 00 0100 00 0101 00 0110 00 0111 00 1000 00 1001 00 1010 00 1011 00 1100 00 1101 00 1110 00 1111 01 0000 01 0001 01 0010 01 0011 01 0100 01 0101 01 0110 01 0111 01 1000 01 1001 01 1010 01 1011 01 1100 01 1101 01 1110 01 1111 10 0000 10 0001 10 0010 10 0011 10 0100 10 0101 10 0110 10 0111 10 1000 10 1001 10 1010 10 1011 10 1100 10 1101 10 1110 10 1111 11 0000 11 0001 11 0010 11 0011 11 0100 Name Config2 RegChk I V P PAVG IRMS VRMS QAVG Q S PF T PSUM SSUM QSUM IDCOFF IGAIN VDCOFF VGAIN POFF IACOFF Epsilon SampleCount - Description1 Configuration 2 Register Checksum I Instantaneous Current V Instantaneous Voltage Instantaneous Power Active Power I RMS Current V RMS Voltage Reserved Reserved Reserved Reserved Reserved Reserved Reactive Power Instantaneous Reactive Power Reserved Reserved Reserved Reserved Apparent Power Power Factor Reserved Reserved Reserved Reserved Reserved Temperature Reserved Total Active Power Total Apparent Power Total Reactive Power I DC Offset I Gain V DC Offset V Gain Instantaneous Power Offset I AC Offset Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Ratio of Line to Sample Frequency Reserved Sample Count Reserved DSP3 Y N N N N N N N HOST 3 Y Y Y Y Y Y Y Y N N Y Y N N Y Y N Y N N N Y Y Y Y Y Y Y Y Y Y Y Y Y N Y N Y Default 0x 10 0200 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 00 0000 0x 40 0000 0x 00 0000 0x 40 0000 0x 00 0000 0x 00 0000 0x 01 999A 0x 00 0FA0 DS982F2 CS5490 53 54* 55* 56* 57 58* 59* 60* 61 62 63 Notes: 11 0101 11 0110 11 0111 11 1000 11 1001 11 1010 11 1011 11 1100 11 1101 11 1110 11 1111 TGAIN TOFF TSETTLE LoadMIN SYSGAIN Time - Reserved Temperature Gain Temperature Offset Reserved Filter Settling Time to Conv. Startup No Load Threshold Reserved System Gain System Time (in samples) Reserved Reserved Y Y Y Y Y Y Y Y N N Y Y 0x 06 B716 0x D5 3998 0x 00 001E 0x 00 0000 0x 50 0000 0x 00 0000 - (1) Warning: Do not write to unpublished or reserved register locations. (2) * Registers with checksum protection. (3) Registers that can be set to write protect from DSP and/or HOST. 6.4 Software Registers Summary (Page 17) Address2 0* 1* 2 3 4* 5* 6 7 8* 9* 10 11 12* 13* 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RA[5:0] 00 0000 00 0001 00 0010 00 0011 00 0100 00 0101 00 0110 00 0111 00 1000 00 1001 00 1010 00 1011 00 1100 00 1101 00 1110 00 1111 01 0000 01 0001 01 0010 01 0011 01 0100 01 0101 01 0110 01 0111 01 1000 01 1001 01 1010 01 1011 01 1100 01 1101 01 1110 01 1111 Notes: (1) Warning: Do not write to unpublished or reserved register locations. Name VSagDUR VSagLevel IOverDUR IOverLEVEL - Description1 V Sag Duration V Sag Level Reserved Reserved I Overcurrent Duration I Overcurrent Level Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved DSP3 Y Y Y Y HOST 3 Default Y 0x 00 0000 Y 0x 00 0000 Y 0x 00 0000 Y 0x 7F FFFF - (2) * Registers with checksum protection. (3) Registers that can be set to write protect from DSP and/or HOST. DS982F2 29 CS5490 6.5 Software Registers Summary (Page 18) Address2 24* 25 26 27 28* 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43* 44 45 46* 47* 48 49 50* 51* 52 53 54 55 56 57 58* 59 60 61 62* 63* RA[5:0] 01 1000 01 1001 01 1010 01 1011 01 1100 01 1101 01 1110 01 1111 10 0000 10 0001 10 0010 10 0011 10 0100 10 0101 10 0110 10 0111 10 1000 10 1001 10 1010 10 1011 10 1100 10 1101 10 1110 10 1111 11 0000 11 0001 11 0010 11 0011 11 0100 11 0101 11 0110 11 0111 11 1000 11 1001 11 1010 11 1011 11 1100 11 1101 11 1110 11 1111 Notes: (1) Warning: Do not write to unpublished or reserved register locations. Name IZXLEVEL PulseRate INTGAIN VSwellDUR VSwellLEVEL VZXLEVEL CycleCount Scale Description1 DSP3 I-channel Zero-crossing Threshold Y Reserved Reserved Reserved Energy Pulse Rate Y Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Rogowski Coil Integrator Gain Y Reserved Reserved V Swell Duration Y V Swell Level Y Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved V-channel Zero-crossing Threshold Y Reserved Reserved Reserved Line Cycle Count N Scale Value for I-channel Gain Calibration Y HOST 3 Default Y 0x 10 0000 Y 0x 80 0000 Y 0x 14 3958 Y 0x 00 0000 Y 0x 7F FFFF Y 0x 10 0000 Y 0x 00 0064 Y 0x 4C CCCC (2) * Registers with checksum protection. (3) Registers that can be set to write protect from DSP and/or HOST. 30 DS982F2 CS5490 6.6 Register Descriptions 21. “Default” = bit states after power-on or reset 22. DO NOT write a “1” to any unpublished register bit or to a bit published as “0”. 23. DO NOT write a “0” to any bit published as “1”. 24. DO NOT write to any unpublished register address. 6.6.1 Configuration 0 (Config0) – Page 0, Address 0 23 1 22 1 21 0 20 0 19 - 18 - 17 - 16 - 15 - 14 0 13 1 12 - 11 - 10 - 9 - 8 INT_POL 7 - 6 - 5 IPGA[1] 4 IPGA[0] 3 - 2 NO_OSC 1 0 0 0 Default = 0xC0 2000 [23:9] Reserved. INT_POL Interrupt Polarity. 0 = Active low (Default) 1 = Active high [7:6] Reserved. IPGA[1:0] Select PGA gain for I channel. 00 = gain (Default) 10 = 50x gain [3] Reserved. NO_OSC Disable crystal oscillator (making XIN a logic-level input). 0 = Crystal oscillator enabled (Default) 1 = Crystal oscillator disabled DS982F2 31 CS5490 6.6.2 Configuration 1 (Config1) – Page 0, Address 1 23 0 22 0 21 0 20 EPG_ON 19 0 18 0 17 0 16 DO_OD 15 1 14 1 13 1 12 0 11 1 10 1 9 1 8 0 7 1 6 1 5 1 4 0 3 DOMODE[3] 2 DOMODE[2] 1 DOMODE[1] 0 DOMODE[0] Default = 0x00 EEEE 32 [23:21] Reserved. EPG_ON Enable EPG block. 0 = Disable energy pulse generation block (Default) 1 = Enable energy pulse generation block [19:17] Reserved. DO_OD Allow the DO pin to be an open-drain output. 0 = Normal output (Default) 1 = Open-drain output [15:4] Reserved. DOMODE[3:0] Output control for DO pin. 0000 = Energy pulse generation (EPG) block output 0001 = Reserved 0010 = Reserved 0011 = Reserved 0100 = P sign 0101 = Reserved 0110 = PSUM sign 0111 = Q sign 1000 = Reserved 1001 = QSUM sign 1010 = Reserved 1011 = V zero-crossing 1100 = I zero-crossing 1101 = Reserved 1110 = Hi-Z, pin not driven (Default) 1111 = Interrupt DS982F2 CS5490 6.6.3 Configuration 2 (Config2) – Page 16, Address 0 23 - 22 POS 21 - 20 1 19 - 18 0 17 0 16 - 15 - 14 APCM 13 - 12 ZX_LPF 11 AVG_MODE 10 REG_CSUM_OFF 9 AFC 8 0 7 0 6 0 5 0 4 IFLT[1] 3 IFLT[0] 2 VFLT[1] 1 VFLT[0] 0 IIR_OFF Default = 0x10 0200 [23] Reserved. POS Positive energy only. Suppress negative values in PAVG . If a negative value is calculated, a zero result will be stored. 0 = Positive and negative energy (Default) 1 = Positive energy only [21:15] Reserved. APCM Selects the apparent power calculation method. 0 = VRMS x IRMS (Default) 1 = SQRT(PAVG2 + QAVG2) [13] Reserved. ZX_LPF Enable LPF in zero-cross detect. 0 = LPF disabled (Default) 1 = LPF enabled AVG_MODE Select averaging mode for low-rate calculations. 0 = Use SampleCount (Default) 1 = Use CycleCount REG_CSUM_OFF Disable checksum on critical registers. 0 = Enable checksum on critical registers (Default) 1 = Disable checksum on critical registers AFC Enables automatic line frequency measurement which sets Epsilon every time a new line frequency measurement completes. Epsilon is used to control the gain of 90° phase shift integrator used in quadrature power calculations. 0 = Disable automatic line frequency measurement 1 = Enable automatic line frequency measurement (Default) [8:5] Reserved. IFLT[1:0] Filter enable for current channel. 00 = No filter (Default) 01 = High-pass filter (HPF) on current channel 10 = Phase-matching filter (PMF) on current channel 11 = Rogowski coil integrator (INT) on current channel VFLT[1:0] Filter enable for voltage channel. 00 = No filter (Default) 01 = High-pass filter (HPF) on voltage channel 10 = Phase-matching filter (PMF) on voltage channel 11 = Reserved IIR_OFF[0] Bypass IIR filter. 0 = Do not bypass IIR filter (Default) 1 = Bypass IIR filter DS982F2 33 CS5490 6.6.4 Phase Compensation (PC) – Page 0, Address 5 23 - 22 - 21 CPCC[1] 20 CPCC[0] 19 - 18 - 17 - 16 - 15 - 14 - 13 - 12 - 11 - 10 - 9 - 8 FPCC[8] 7 6 5 4 3 2 1 0 FPCC[7] FPCC[6] FPCC[5] FPCC[4] FPCC[3] FPCC[2] FPCC[1] FPCC[0] Default = 0x00 0000 [23:22] Reserved. CPCC[1:0] Coarse phase compensation control for I & V. 00 = No extra delay 01 = 1 OWR delay in current channel 10 = 1 OWR delay in voltage channel 11 = 2 OWR delay in voltage channel [19:9] Reserved. FPCC[8:0] Fine phase compensation control for I & V. Sets a delay in current, relative to voltage. Resolution: 0.008789° at 50Hz and 0.010547° at 60Hz (OWR = 4000) 6.6.5 UART Control (SerialCtrl) – Page 0, Address 7 23 - 22 - 21 - 20 - 19 - 18 17 RX_PU_OFF RX_CSUM_OFF 16 - 15 BR[15] 14 BR[14] 13 BR[13] 12 BR[12] 11 BR[11] 10 BR[10] 9 BR[9] 8 BR[8] 7 BR[7] 6 BR[6] 5 BR[5] 4 BR[4] 3 BR[3] 2 BR[2] 1 BR[1] 0 BR[0] Default = 0x02 004D [23:19] Reserved. RX_PU_OFF Disable the pull-up resistor on the RX input pin. 0 = Pull-up resistor enabled (Default) 1 = Pull-up resistor disabled RX_CSUM_OFF Disable the checksum on serial port data. 0 = Enable checksum 1 = Disable checksum (Default) 34 [16] Reserved. BR[15:0] Baud rate (serial bit rate). BR[15:0] = Baud Rate x 524288 / MCLK DS982F2 CS5490 6.6.6 Pulse Output Width (PulseWidth) – Page 0, Address 8 23 - 22 - 21 - 20 - 19 18 17 16 FREQ_RNG[3] FREQ_RNG[2] FREQ_RNG[1] FREQ_RNG[0] 15 PW[15] 14 PW[14] 13 PW[13] 12 PW[12] 11 PW[11] 10 PW[10] 9 PW[9] 8 PW[8] 7 6 5 4 3 2 1 0 PW[7] PW[6] PW[5] PW[4] PW[3] PW[2] PW[1] PW[0] Default = 0x00 0001 (265.6µs at OWR = 4kHz) PulseWidth sets the energy pulse frequency range and the duration of energy pulses. The actual pulse duration is 250µs plus the contents of PulseWidth divided by 64,000. PulseWidth is an integer in the range of 1 to 65,535. [23:20] Reserved. FREQ_RNG[19:16] Energy pulse (PulseRate) frequency range for 0.1% resolution. 0000 = Freq. range: 2 kHz – 0.238 Hz (Default) 0001 = Freq. range: 1 kHz – 0.1192 Hz 0010 = Freq. range: 500 Hz – 0.0596 Hz 0011 = Freq. range: 250Hz–0.0298Hz 0100 = Freq. range: 125 Hz – 0.0149 Hz 0101 = Freq. range: 62.5 Hz – 0.00745 Hz 0110 = Freq. range: 31.25 Hz – 0.003725 Hz 0111 = Freq. range: 15.625 Hz – 0.0018626 Hz 1000 = Freq. range: 7.8125 Hz – 0.000931323 Hz 1001 = Freq. range: 3.90625 Hz – 0.000465661 Hz 1010 = Reserved ... 1111 = Reserved PW[15:0] Energy Pulse Width. 6.6.7 Pulse Output Rate (PulseRate) – Page 18, Address 28 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default= 0x80 0000 PulseRate sets the full-scale frequency for the energy pulse output. For a 4 kHz OWR rate, the maximum pulse rate is 2 kHz. It is a two's complement value in the range of -1 value 1, with the binary point to the left of the MSB. Refer to section 5.5 Energy Pulse Generation on page 19 for more information. DS982F2 35 CS5490 6.6.8 Pulse Output Control (PulseCtrl) – Page 0, Address 9 23 - 22 - 21 - 20 - 19 - 18 - 17 - 16 - 15 0 14 0 13 0 12 0 11 0 10 0 9 0 8 0 7 6 5 4 3 2 1 0 0 0 0 0 EPGIN[3] EPGIN[2] EPGIN[1] EPGIN[0] Default = 0x00 0000 This register controls the input to the energy pulse generation (EPG) block. [23:4] Reserved. EPGIN[3:0] Selects the input to the energy pulse generation (EPG) block. 0000 = PAVG (Default) 0001 = Reserved 0010 = PSUM 0011 = QAVG 0100 = Reserved 0101 = QSUM 0110 = S 0111 = Reserved 1000 = SSUM 1001 = Unused ... 1111 = Unused 6.6.9 Register Lock Control (RegLock) – Page 0, Address 34 23 - 22 - 21 - 20 - 19 - 18 - 17 - 16 - 15 - 14 - 13 - 12 DSP_LCK[4] 11 DSP_LCK[3] 10 DSP_LCK[2] 9 DSP_LCK[1] 8 DSP_LCK[0] 7 6 5 4 3 2 1 0 - - - HOST_LCK[4] HOST_LCK[3] HOST_LCK[2] HOST_LCK[1] HOST_LCK[0] Default = 0x00 0000 [23:13] Reserved. DSP_LCK[12:8] DSP_LCK[4:0] = 0x16 sets the DSP lockable registers to be write protected from the CS5490 internal calculation engine. Writing 0x09 unlocks the registers. [7:5] Reserved. HOST_LCK[4:0] HOST_LCK[4:0] = 0x16 sets all the registers except RegLock, Status0, Status1, and Status2 to be write protected from the serial interface. Writing 0x09 unlocks the registers. 36 DS982F2 CS5490 6.6.10 Phase Sequence Detection and Control (PSDC) – Page 0, Address 48 23 DONE 22 PSCNT[6] 21 PSCNT[5] 20 PSCNT[4] 19 PSCNT[3] 18 PSCNT[2] 17 PSCNT[1] 16 PSCNT[0] 15 - 14 - 13 - 12 - 11 - 10 - 9 - 8 - 7 - 6 - 5 DIR 4 CODE[4] 3 CODE[3] 2 CODE[2] 1 CODE[1] 0 CODE[0] Default = 0x00 0000 DONE Indicates valid count values reside in PSCNT[6:0]. 0 = Invalid values in PSCNT[6:0]. (Default) 1 = Valid values in PSCNT[6:0]. PSCNT[6:0] Registers the number of OWR samples from the start time to the time when the next zero crossing is detected. [15:6] Reserved. DIR Set the zero-crossing edge direction which will stop PSCNT count. 0 = Stop count at negative to positive zero-crossing - Rising Edge. (Default) 1 = Stop count at positive to negative zero-crossing - Falling Edge. CODE[4:0] Write 10110 to this location to enable the phase sequence detection. 6.6.11 Checksum of Critical Registers (RegChk) – Page 16, Address 1 MSB 223 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0000 This register contains the checksum of critical registers. DS982F2 37 CS5490 6.6.12 Interrupt Status (Status0) – Page 0, Address 23 23 DRDY 22 CRDY 21 WOF 20 - 19 - 18 MIPS 17 - 16 VSWELL 15 - 14 POR 13 - 12 IOR 11 - 10 VOR 9 - 8 IOC 7 - 6 VSAG 5 TUP 4 FUP 3 IC 2 RX_CSUM_ERR 1 - 0 RX_TO Default = 0x 00 0000 The Status0 register indicates a variety of conditions within the chip. Writing a one to a Status0 register bit will clear that bit. Writing a zero to any bit has no effect. DRDY Data Ready. During conversion, this bit indicates that low-rate results have been updated. It indicates completion of other host instruction and the reset sequence. CRDY Conversion Ready. Indicates that sample rate (output word rate) results have been updated. WOF Watchdog timer overflow. [20:19] Reserved. MIPS MIPS overflow. Sets when the calculation engine has not completed processing a sample before the next one arrives. [17] Reserved. VSWELL Voltage channel swell event detected. [15] Reserved. POR Power out of range. Sets when the measured power would cause the P register to overflow. [13] Reserved. IOR Current out of range. Set when the measured current would cause the I register to overflow. [11] Reserved. VOR Voltage out of range. Set when the measured voltage would cause the V register to overflow. [7] Reserved. IOC I Overcurrent. [9] Reserved. VSAG Voltage channel sag event detected. TUP Temperature updated. Indicates when the Temperature register (T) has been updated. FUP Frequency updated. Indicates the Epsilon register has been updated. IC Invalid command has been received. RX_CSUM_ERR Received data checksum error. Sets to one automatically if checksum error is detected on serial port received data. RX_TO 38 SDI/RX time out. Sets to one automatically when SDI/RX time out occurs. DS982F2 CS5490 6.6.13 Interrupt Mask (Mask) – Page 0, Address 3 23 DRDY 22 CRDY 21 WOF 20 - 19 - 18 MIPS 17 0 16 VSWELL 15 0 14 POR 13 0 12 IOR 11 0 10 VOR 9 0 8 IOC 7 0 6 VSAG 5 TUP 4 FUP 3 IC 2 RX_CSUM_ERR 1 - 0 RX_TO Default = 0x00 0000 The Mask register is used to control the activation of the INT pin. Writing a '1' to a Mask register bit will allow the corresponding Status0 register bit to activate the INT pin when set. [23:0] Enable/disable (mask) interrupts. 0 = Interrupt disabled (Default) 1 = Interrupt enabled 6.6.14 Chip Status 1 (Status1) – Page 0, Address 24 23 22 21 - 20 - 19 - 18 - 17 - 16 - 15 LCOM[7] 14 LCOM[6] 13 LCOM[5] 12 LCOM[4] 11 LCOM[3] 10 LCOM[2] 9 LCOM[1] 8 LCOM[0] 7 - 6 - 5 - 4 - 3 TOD 2 VOD 1 - 0 IOD Default = 0x00 0000 This register indicates a variety of conditions within the chip. [23:16] Reserved. LCOM[15:8] Indicates the value of the last serial command executed. [7:4] Reserved. TOD Modulator oscillation has been detected in the temperature ADC. VOD Modulator oscillation has been detected in the voltage ADC. [1] Reserved. IOD Modulator oscillation has been detected in the current ADC. DS982F2 39 CS5490 6.6.15 Chip Status 2 (Status2) – Page 0, Address 25 23 - 22 - 21 - 20 - 19 - 18 - 17 - 16 - 15 - 14 - 13 - 12 - 11 - 10 - 9 - 8 - 7 - 6 - 5 QSUM_SIGN 4 - 3 Q_SIGN 2 PSUM_SIGN 1 - 0 P_SIGN Default = 0x00 0000 This register indicates a variety of conditions within the chip. [23:6] Reserved. QSUM_SIGN Indicates the sign of the value contained in QSUM. 0 = positive value 1 = negative value [4] Reserved. Q_SIGN Indicates the sign of the value contained in QAVG. 0 = positive value 1 = negative value PSUM_SIGN Indicates the sign of the value contained in PSUM. 0 = positive value 1 = negative value [1] Reserved. P_SIGN Indicates the sign of the value contained in PAVG. 0 = positive value 1 = negative value 6.6.16 Line to Sample Frequency Ratio (Epsilon) – Page 16, Address 49 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x01 999A (0.0125 or 50Hz/4.0kHz) Epsilon is the ratio of the input line frequency to the output word rate (OWR). It can either be written by the application program or calculated automatically from the line frequency (from the voltage channel input) using the AFC bit in the Config2 register. It is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used. 40 DS982F2 CS5490 6.6.17 No Load Threshold (LoadMIN) – Page 16, Address 58 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 LoadMIN is used to set the no-load threshold for the anti-creep function. When the magnitudes of PSUM and QSUM are less than LoadMIN, PSUM and QSUM are forced to zero. When the magnitude of SSUM is less than LoadMIN, SSUM is forced to zero. LoadMIN is a two’s complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used. 6.6.18 Sample Count (SampleCount) – Page 16, Address 51 MSB 0 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0FA0 (4000) Determines the number of output word rate (OWR) samples to use in calculating low-rate results. SampleCount (N) is an integer in the range of 100 to 8,388,607. Values less than 100 should not be used. 6.6.19 Cycle Count (CycleCount) – Page 18, Address 62 MSB 0 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0064 (100) Determines the number of half-line cycles to use in calculating low-rate results when the CS5490 is in Line-cycle Synchronized Averaging mode. CycleCount is an integer in the range of 1 to 8,388,607. Zero should not be used. 6.6.20 Filter Settling Time for Conversion Startup (TSETTLE ) – Page 16, Address 57 MSB 223 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 001E (30) Sets the number of output word rate (OWR) samples that will be used to allow filters to settle at the beginning of Conversion and Calibration commands. This is an integer in the range of 0 to 16,777,215 samples. DS982F2 41 CS5490 6.6.21 System Gain (SysGAIN ) – Page 16, Address 60 MSB -(21) LSB 20 2-1 2-2 2-3 2-4 2-5 2-6 ..... 2-16 2-17 2-18 2-19 2-20 2-21 2-22 Default = 0x50 0000 (1.25) System Gain (SysGAIN ) is applied to all channels. By default, SysGAIN = 1.25, but can be finely adjusted to compensate for voltage reference error. It is a two's complement value in the range of -2.0 value 2.0, with the binary point to the right of the second MSB. Values should be kept within 5% of 1.25. 6.6.22 Rogowski Coil Integrator Gain (IntGAIN ) – Page 18, Address 43 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x14 3958 Gain for the Rogowski coil integrator. This must be programmed accordingly for 50Hz and 60Hz (0.158 for 50Hz, 0.1875 for 60Hz). This is a two’s complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used. 6.6.23 System Time (Time) – Page 16, Address 61 MSB 223 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0000 System Time (Time) is measured in output word rate (OWR) samples. This is an unsigned integer in the range of 0 to 16,777,215 samples. At OWR = 4.0 kHz, OWR will overflow every 1 hour, 9 minutes, 54 seconds. Time can be used by the application to manage real-time events. 6.6.24 Voltage Sag Duration (VSagDUR ) – Page 17, Address 0 MSB 0 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0000 Voltage sag duration, VSagDUR, determines the count of output word rate (OWR) samples utilized to determine a sag event. These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature. 42 DS982F2 CS5490 6.6.25 Voltage Sag Level (VSagLEVEL ) – Page 17, Address 1 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Voltage sag level, VSagLEVEL, establishes an input level below which a sag event is triggered. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used. 6.6.26 Current Overcurrent Duration (IOverDUR ) – Page 17, Address 4 MSB 0 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0000 Overcurrent duration, IOverDUR, determines the count of output word rate (OWR) samples utilized to determine an overcurrent event. These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature. 6.6.27 Current Overcurrent Level (IOverLEVEL ) – Page 17, Address 5 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x7F FFFF Overcurrent level, IOverLEVEL, establishes an input level above which an overcurrent event is triggered. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used. 6.6.28 Voltage Swell Duration (VSwellDUR ) – Page 18, Address 46 MSB 0 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0000 Voltage swell duration, VSwellDUR, determines the count of output word rate (OWR) samples used to determine a swell event. These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature. DS982F2 43 CS5490 6.6.29 Voltage Swell Level (VSwellLEVEL ) – Page 18, Address 47 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x7F FFFF Voltage swell level, VSwellLEVEL, establishes an input level above which a swell event is triggered. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used. 6.6.30 Instantaneous Current (I) – Page 16, Address 2 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 I contains instantaneous current measurements for current channel. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.31 Instantaneous Voltage (V) – Page 16, Address 3 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 V contains instantaneous voltage measurements for voltage channel. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.32 Instantaneous Active Power (P) – Page 16, Address 4 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 P contains instantaneous power measurements for current and voltage channels. Values in registers I and V are multiplied to generate this value. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 44 DS982F2 CS5490 6.6.33 Active Power (PAVG) – Page 16, Address 5 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Instantaneous power is averaged over each low-rate interval (SampleCount samples) and then added with power offset (POFF) to compute active power (PAVG). This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.34 RMS Current (IRMS ) – Page 16, Address 6 MSB 2-1 LSB 2-2 2-3 2-4 2-5 2-6 2-7 2-8 ..... 2-18 2-19 2-20 2-21 2-22 2-23 2-24 Default = 0x00 0000 IRMS contains the root mean square (RMS) values of I, calculated during each low-rate interval. This is an unsigned value in the range of 0value1.0, with the binary point to the left of the MSB. 6.6.35 RMS Voltage (VRMS ) – Page 16, Address 7 MSB 2-1 LSB 2-2 2-3 2-4 2-5 2-6 2-7 2-8 ..... 2-18 2-19 2-20 2-21 2-22 2-23 2-24 Default = 0x00 0000 VRMS contains the root mean square (RMS) value of V, calculated during each low-rate interval. This is an unsigned value in the range of 0value1.0, with the binary point to the left of the MSB. 6.6.36 Reactive Power (QAvg ) – Page 16, Address 14 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Reactive power (QAVG) is Q averaged over each low-rate interval (SampleCount samples) and corrected by QOFF. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. DS982F2 45 CS5490 6.6.37 Instantaneous Quadrature Power (Q) – Page 16, Address 15 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Instantaneous quadrature power, Q, the product of V shifted 90° and I. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.38 Peak Current (IPEAK) – Page 0, Address 37 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Peak current (IPEAK) contains the value of the instantaneous current 1 sample with the greatest magnitude detected during the last low-rate interval. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.39 Peak Voltage (VPEAK) – Page 0, Address 36 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Peak voltage (VPEAK) contains the value of the instantaneous voltage sample with the greatest magnitude detected during the last low-rate interval. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.40 Apparent Power (S) – Page 16, Address 20 MSB 0 LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Apparent power 1 (S) is the product of VRMS and IRMS or SQRT(PAVG2 + QAVG2 ). This is an unsigned value in the range of 0 value 1.0, with the binary point to the right of the MSB. 46 DS982F2 CS5490 6.6.41 Power Factor (PF) – Page 16, Address 21 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Power factor (PF) is calculated by dividing active power (PAVG) by apparent power (S). The sign is determined by the active power (PAVG) sign. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.42 Temperature (T) – Page 16, Address 27 MSB LSB -(27) 26 25 24 23 22 21 20 ..... 2-10 2-11 2-12 2-13 2-14 2-15 2-16 Default = 0 T contains results from the on-chip temperature measurement. By default, T uses the Celsius scale and is a two's complement value in the range of -128.0 value 128.0 (°C), with the binary point to the right of bit 16. T can be rescaled by the application using the TGAIN and TOFF registers. 6.6.43 Total Active Power (PSUM ) – Page 16, Address 29 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0 PSUM = PAVG This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.44 Total Apparent Power (SSUM ) – Page 16, Address 30 MSB 0 LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0 SSUM = S This is an unsigned value in the range of 0value1.0, with the binary point to the right of the MSB. DS982F2 47 CS5490 6.6.45 Total Reactive Power (QSUM ) – Page 16, Address 31 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0 QSUM = QAVG This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.46 DC Offset for Current (IDCOFF ) – Page 16, Address 32 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0 DC offset registers IDCOFF are initialized to zero on reset. During DC offset calibration, selected registers are written with the inverse of the DC offset measured. The application program can also write the DC offset register values. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.47 DC Offset for Voltage (VDCOFF ) – Page 16, Address 34 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0 DC offset registers VDCOFF are initialized to zero on reset. During DC offset calibration, selected registers are written with the inverse of the DC offset measured. The application program can also write the DC offset register values. It is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.48 Gain for Current (IGAIN ) – Page 16, Address 33 MSB 21 LSB 20 2-1 2-2 2-3 2-4 2-5 2-6 ..... 2-16 2-17 2-18 2-19 2-20 2-21 2-22 Default = 1.0 Gain register IGAIN is initialized to 1.0 on reset. During gain calibration, the IGAIN register is written with the multiplicative inverse of the gain measured. This is an unsigned fixed-point value in the range of 0 value 4.0, with the binary point to the right of the second MSB. 48 DS982F2 CS5490 6.6.49 Gain for Voltage (VGAIN ) – Page 16, Address 35 MSB LSB 21 20 2-1 2-2 2-3 2-4 2-5 2-6 ..... 2-16 2-17 2-18 2-19 2-20 2-21 2-22 Default = 1.0 Gain register VGAIN is initialized to 1.0 on reset. During gain calibration, the VGAIN register is written with the multiplicative inverse of the gain measured. This is an unsigned fixed-point value in the range of 0 value 4.0, with the binary point to the right of the second MSB. 6.6.50 Average Active Power Offset (POFF ) – Page 16, Address 36 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0 Average Active Power Offset (POFF) is added to the averaged active power to yield PAVG register results. It can be used to reduce systematic energy errors. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.51 Average Reactive Power Offset (QOFF ) – Page 16, Address 38 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x00 0000 Average Reactive Power Offset (QOFF) is added to the averaged active power to yield QAVG register results. It can be used to reduce systematic energy errors. It is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. 6.6.52 AC Offset for Current (IACOFF ) – Page 16, Address 37 MSB 2-1 LSB 2-2 2-3 2-4 2-5 2-6 2-7 2-8 ..... 2-18 2-19 2-20 2-21 2-22 2-23 2-24 Default = 0 AC offset register IACOFF is initialized to zero on reset. It is used to reduce systematic errors in the RMS results. This is an unsigned value in the range of 0 value 1.0, with the binary point to the left of the MSB. 6.6.53 Temperature Gain (TGAIN ) – Page 16, Address 54 MSB LSB 27 26 25 24 23 22 21 20 ..... 2-10 2-11 2-12 2-13 2-14 2-15 2-16 Default = 0x 06 B716 Register TGAIN is used to scale the Temperature register (T), and is an unsigned fixed-point value in the range of 0.0value256.0, with the binary point to the right of bit 16. Register T can be rescaled by the application using the TGAIN and TOFF registers. Refer to section 7.3 Temperature Sensor Calibration on page 53 for more information. DS982F2 49 CS5490 6.6.54 Temperature Offset (TOFF ) – Page 16, Address 55 MSB -(27) LSB 26 25 24 23 22 21 20 ..... 2-10 2-11 2-12 2-13 2-14 2-15 2-16 Default = 0xD5 3998 Register TOFF is used to offset the Temperature register (T), and is a two's complement value in the range of -128.0value128.0 (°C), with the binary point to the right of bit 16. Register T can be rescaled by the application using the TGAIN and TOFF registers. Refer to section 7.3 Temperature Sensor Calibration on page 53 for more information. 6.6.55 Calibration Scale (Scale) – Page18, Address 63 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x4C CCCC (0.6) The Scale register is used in the gain calibration to set the level of calibrated results of I-channel RMS. During gain calibration, the IRMS results register is divided into the Scale register. The quotient is put into the IGAIN register. It is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used. 6.6.56 Zero-crossing Number (ZXNUM) – Page 0, Address 55 MSB 223 LSB 222 221 220 219 218 217 216 ..... 26 25 24 23 22 21 20 Default = 0x00 0064 (100) ZXNUM is the number of zero crossings used for line frequency measurement. It is an integer in the range of 1 to 8,388,607. Zero should not be used. 6.6.57 V-channel Zero-crossing Threshold (VZXLEVEL) – Page 18, Address 58 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x10 0000 (0.125) VZXLEVEL is the level that the peak instantaneous voltage must exceed for the zero-crossing detection to function. This is a two's complement value in the range of -1.0 value<1.0, with the binary point to the right of the MSB. Negative values are not used. 6.6.58 I-channel Zero-crossing Threshold (IZXLEVEL) – Page 18, Address 24 MSB -(20) LSB 2-1 2-2 2-3 2-4 2-5 2-6 2-7 ..... 2-17 2-18 2-19 2-20 2-21 2-22 2-23 Default = 0x10 0000 (0.125) IZXLEVEL is the level that the peak instantaneous current must exceed for the zero-crossing detection to function. This is a two's complement value in the range of -1.0 value<1.0, with the binary point to the right of the MSB. Negative values are not used. 50 DS982F2 CS5490 7. SYSTEM CALIBRATION samples that are averaged during a calibration. The calibration procedure takes the time of N + TSETTLE OWR samples. As N is increased, the calibration takes more time, but the accuracy of the calibration results tends to increase. Component tolerances, residual ADC offset, and system noise require a meter that needs to be calibrated before it meets a specific accuracy requirement. The CS5490 provides an on-chip calibration algorithm to operate the system calibration quickly and easily. Benefiting from the excellent linearity and low noise level of the CS5490, a CS5490 meter normally only needs one calibration at a single load point to achieve accurate measurements over the full load range. The DRDY bit in the Status0 register will be set at the completion of calibration commands. If an overflow occurs during calibration, other Status0 bits may be set as well. 7.1 Calibration in General 7.1.1 Offset Calibration The CS5490 provides DC offset and gain calibration that can be applied to the instantaneous voltage and current measurements and AC offset calibration, which can only be applied to the current RMS calculation. During offset calibrations, no line voltage or current should be applied to the meter; the differential signal on voltage inputs VIN± or current inputs IIN± of the CS5490 should be 0 volts. Since the voltage and current channels have independent offset and gain registers, offset and gain calibration can be performed on any channel independently. 7.1.1.1 DC Offset Calibration The DC offset calibration command measures and averages DC values read on specified voltage or current channels at zero input and stores the inverse result in the associated offset registers. This DC offset will be added to instantaneous measurements in subsequent conversions, removing the offset. The data flow of the calibration is shown in Figure 19. Note that in Figure 19 the AC offset registers and gain registers affect the output results differently than the DC offset registers. The DC offset and gain values are applied to the voltage/current signals early in the signal path; the DC offset register and gain register values affect all CS5490 results. This is not true for the AC offset correction. The AC offset registers only affect the results of the RMS current calculation. The gain register for the channel being calibrated should be set to 1.0 prior to performing DC offset calibration. DC offset calibration is not required if the high-pass filter is enabled on that channel because the DC component will be removed by the high-pass filter. The CS5490 must be operating in its active state and ready to accept valid commands. Refer to section 6.1.2 Instructions on page 24 for different calibration commands. The value in the SampleCount register determines the number (N) of output word rate (OWR) 7.1.1.2 AC Offset Calibration The AC offset calibration applies only to the current channel. It measures the residual RMS values on the current channel at zero input and stores the squared V*, I*, P*, Q* Registers IN Modulator N Filter IDCOFF *, VDCOFF* Registers IGAIN*, VGAIN* Registers VRMS* , IRMS* Registers N N -1 I ACOFF *Ϯ Register N -1 * Denotes readable/writable register Ϯ Applies only to the current path (I1, I2) DC 0.6(Scale *Ϯ) RMS RMS Figure 19. Calibration Data Flow DS982F2 51 CS5490 result in the AC offset register. This AC offset will be subtracted from RMS measurements in subsequent conversions, removing the AC offset on the current channel. The AC offset register for the channel being calibrated should first be cleared prior to performing the calibration. The high-pass filter should be enabled if AC offset calibration is used. It is recommended that TSETTLE be set to 2000ms before performing an AC offset calibration. Note that the AC offset register holds the square of the RMS value measured during calibration. Therefore, it can hold a maximum RMS noise of 0xFFFFFF . This is the maximum RMS noise that AC offset correction can remove. 7.1.2 Gain Calibration Prior to executing the gain calibration command, gain registers for any path to be calibrated (VGAIN, IGAIN) should be set to ‘1.0,’ and TSETTLE should be set to 2000 ms. For gain calibration, a reference signal must be applied to the meter. During gain calibration, the voltage RMS result register (VRMS) is divided into ‘0.6,’ and the current RMS result register (IRMS) is divided into the Scale register. The quotient is put into the associated gain register. The gain calibration algorithm attempts to adjust the gain register (VGAIN, IGAIN) such that the voltage RMS result register (VRMS) equals ‘0.6,’ and the current RMS result register (IRMS) equals the Scale register. Note that for the gain calibration, there are limitations on choosing the reference level and the Scale register value. Using a reference or a scale that is too large or too small can cause register overflow during calibration or later during normal operation. Either condition can set Status register bits IOR and VOR. The maximum value that the gain register can attain is ‘4.’ Using inappropriate reference levels or scale values may also cause the CS5490 to attempt to set the gain register higher than ‘4.’ Therefore, the gain calibration result will be invalid. The Scale register is ‘0.6’ by default. The maximum voltage (UMAX Volts) and current (IMAX Amps) of the meter should be used as the reference signal level if the Scale register is ‘0.6.’ After gain calibration, ‘0.6’ of the VRMS (IRMS) registers represents UMAX Volts (IMAX Amps) for the line voltage (load current); ‘0.36’ of the PAVG, QAVG, or S register represents UMAX × IMAX Watts, Vars, or VAs for the active, reactive, or apparent power. If the calibration is performed with U MAX Volts and ICAL Amps and ICAL < I MAX, the Scale register needs to be scaled down to 0.6 × ICAL / IMAX before performing gain calibration. After gain calibration, ‘0.6’ of the VRMS register represents UMAX Volts, 0.6 x ICAL / IMAX of the IRMS register represents ICAL Amps, and 0.36 x ICAL / IMAX of the PAVG, QAVG, or S register represents UMAX x ICAL Watts, Vars, or VAs. 7.1.3 Calibration Order 1) If the HPF option is enabled, then any DC component that may be present in the selected signal channel will be removed, and a DC offset calibration is not required. However, if the HPF option is disabled, the DC offset calibration should be performed. When using high-pass filters, it is recommended that the DC offset register for the corresponding channel be set to 0. Before performing DC offset calibration, the DC offset register should be set to 0, and the corresponding gain register should be set to 1. 2) If there is an AC offset in the IRMS calculation, the AC offset calibration should be performed on the current channel. Before performing AC offset calibration, the AC offset register should be set to 0. 3) Perform the gain calibration. 4) If an AC offset calibration was performed (step 2), then the AC offset may need to be adjusted to compensate for the change in gain (step 3). This can be accomplished by restoring zero to the AC offset register and then performing an AC offset calibration. The adjustment could also be done by multiplying the AC offset register value that was calculated in step 2 by the gain calculated in step 3 and updating the AC offset register with the product. 7.2 Phase Compensation A phase compensation mechanism is provided to adjust for meter-to-meter variation in signal path delays. Phase offset between a voltage channel and its corresponding current channel can be calculated by using the power factor (PF) register after a conversion. 1) Apply a reference voltage and current with a lagging power factor to the meter. The reference current waveform should lag the voltage with a 60° phase shift. 2) Start continuous conversion. 3) Accumulate multiple readings of the PF register. 4) Calculate the average power factor, PFavg. 5) Calculate phase offset = arccos(PFavg) - 60°. 52 DS982F2 CS5490 Once the phase offset is known, the CPCC and FPCC bits for that channel are calculated and programmed in the PC register. CPCC bits are used if either • The phase offset is more than 1 output word rate (OWR) sample. • More delay is needed on the voltage channel. The compensation resolution is 0.008789° at 50Hz and 0.010547° at 60Hz at an OWR of 4000Hz. 7.3 Temperature Sensor Calibration Temperature sensor calibration involves the adjustment of two parameters: temperature gain (TGAIN) and temperature offset (TOFF). Before calibration, TGAIN must be set to 1.0 (0x 01 0000), and TOFF must be set to 0.0 (0x 00 0000). 7.3.1 Temperature Offset and Gain Calibration To obtain the optimal temperature offset (TOFF) register value and temperature (TGAIN) register value, it is necessary to measure the temperature (T) register at a minimum of two points (T1 and T2) across the meter operating temperature range. The two temperature points must be far enough apart to yield reasonable accuracy, for example 25 °C and 85° C. Obtain a linear fit of these points ( y = m x + b ), where the slope (m) and intercept (b) can be obtained. T2 Y= m •x +b Force Temperature (°C) 6) If the phase offset is negative, then the delay should be added only to the current channel. Otherwise, add more delay to the voltage channel than to the current channel to compensate for a positive phase offset. m T1 b T Register Value Figure 20. T Register vs. Force Temp TOFF and TGAIN are calculated using the equations below: b T OFF = ----m T GAIN = m DS982F2 53 CS5490 8. BASIC APPLICATION CIRCUITS The CS5490 is configured to measure power in a single-phase, two-wire single voltage and current system, as illustrated in Figure 21. In this diagram, a current transformer (CT) is used to sense the line load current, and a resistive voltage divider is used to sense the line voltage. +3.3V +3.3V 0.1µF N 0.1µF VDDA MODE VDDD Line Wh +3.3V 1K 1K 5 x250K DO VIN27nF 27nF VIN+ CS5490 RX TX ½ R BURDEN 1K CT IIN+ 4.096 MHz XOUT ½ R BURDEN 27nF 1K Application Processor XIN 27nF IIN- VREF+ 0.1µF VREF- LOA D +3.3V 10K RESET GNDA 0.1 µF Figure 21. Typical Connection Diagram (Single-phase, Two-wire, Power Meter) 54 DS982F2 CS5490 9. PACKAGE DIMENSIONS 16 SOIC (150 MIL BODY) PACKAGE DRAWING Dimension A A1 b c D E E1 e L Θ aaa bbb ddd MIN -0.10 0.31 0.10 0.40 0° mm NOM ----9.90 BSC 6.00 BSC 3.90 BSC 1.27 BSC --0.10 0.25 0.25 MAX 1.75 0.25 0.51 0.25 MIN -0.004 0.012 0.004 1.27 8° 0.016 0° inch NOM ----0.390 BSC 0.236 BSC 0.154 BSC 0.05 BSC --0.004 0.010 0.010 MAX 0.069 0.010 0.020 0.010 0.050 8° Notes: 1. 2. 3. 4. DS982F2 Controlling dimensions are in millimeters. Dimensions and tolerances per ASME Y14.5M. This drawing conforms to JEDEC outline MS-012, variation AC for standard 16 SOIC narrow body. Recommended reflow profile is per JEDEC/IPC J-STD-020. 55 CS5490 10. ORDERING INFORMATION Ordering Number Container CS5490-ISZ Bulk CS5490-ISZR Tape & Reel Temperature Package -40 to +85 °C 16-pin SOIC, Lead (Pb) Free 11. ENVIRONMENTAL, MANUFACTURING, & HANDLING INFORMATION Part Number Peak Reflow Temp MSL Rating* Max Floor Life CS5490-ISZ 260 °C 3 7 Days * MSL (Moisture Sensitivity Level) as specified by IPC/JEDEC J-STD-020. 12. REVISION HISTORY Revision Date Changes PP1 APR 2012 Preliminary release. F1 APR 2012 Edited for content and clarity. F2 JUN 2012 Updated ordering information. Contacting Cirrus Logic Support For all product questions and inquiries contact a Cirrus Logic Sales Representative. To find the one nearest to you go to www.cirrus.com IMPORTANT NOTICE Cirrus Logic, Inc. and its subsidiaries (“Cirrus”) believe that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided “AS IS” without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. 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IF THE CUSTOMER OR CUSTOMER'S CUSTOMER USES OR PERMITS THE USE OF CIRRUS PRODUCTS IN CRITICAL APPLICATIONS, CUSTOMER AGREES, BY SUCH USE, TO FULLY INDEMNIFY CIRRUS, ITS OFFICERS, DIRECTORS, EMPLOYEES, DISTRIBUTORS AND OTHER AGENTS FROM ANY AND ALL LIABILITY, INCLUDING ATTORNEYS' FEES AND COSTS, THAT MAY RESULT FROM OR ARISE IN CONNECTION WITH THESE USES. Cirrus Logic, Cirrus, the Cirrus Logic logo designs, EXL Core, and the EXL Core logo design are trademarks of Cirrus Logic, Inc. All other brand and product names in this document may be trademarks or service marks of their respective owners. 56 DS982F2