Isolated, Field Configurable Analog Input 6B21 FEATURES Module accepts commands from the host computer and converts it into an isolated process current suitable for interfacing with valves and actuators. Complete microcomputer-based data acquisition systems. Output range can be selected to either a 0 to 20 mA or 4 mA to 20 mA process current. RTD and thermocouple, and a wide variety of input ranges. This reduces the number of different modules that need to be used in a given application and carried in inventory. FUNCTIONAL BLOCK DIAGRAM APPLICATIONS Process Monitoring & Control Test Stand Automation Machine Monitoring Material Testing Remote Energy Mangement Laboratory Data Acquisition PRODUCT OVERVIEW Figure 1. 6B21 Functional Block Diagram The 6B Series delivers sensor-to-host signal-conditioning for remote applications. Software-configurable for a wide variety of sensor types, including: analog input, analog output, and digital I/O, the 6B Series is intended for remote data acquisition, machine monitoring, remote energy management and process monitoring and control applications. Designed for industrial applications, the 6B Series modules incorporate transformer-based isolation with surface-mount manufacturing technology – providing increased reliability at low cost. The compact, rugged 6B Series analog modules can be mixed and matched on a 16-channel backplane for high density, remote process monitoring and control. Including transformer-based isolation, ranging, linearization, A/d conversion and RS-232C/RS-485 serial communication for up to 256 channels per serial port, the 6B Series modules and boards are a complete, low-cost interface between computers and analog signals. Communications between backplanes, modules and host is in ASCII over an RS-232C link or RS-485 bi-directional serial bus. Circuitry to convert RS-232C to RS485 is built into the 6B backplane. Baud rates are software programmable, with speeds up to 19.2 K Baud. All 6B Series input/output modules are fully encapsulated and identical in pin-out and size, facilitating their ability to be mixed and matched with all other 6B Series modules on the same backplane. The 6B Series is fully rated over the industrial temperature range of -25oC to +85oC. The 6B Series digital subsystem communication is compatible with the overall 6B Series communication protocol. Each digital I/O board can be configured for its address, baud rate and checksum status. Connection to the 16 and 24-channel solid state relay backplanes is by a 50-conductor ribbon cable. This enables interfacing with input and outputs from 4 V to 240 V. Power control modules are also available that can switch up to 3A and come with a variety of ratings for low voltage DC up to 280 VAC. Each 6B Series module and board is a complete microcontroller-based process monitoring and control system, with all calibration, address and linearizing parameters stored in non-volatile memory. Being microcontroller-based, 6b Series modules can be configured for various sensor types, including Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective companies. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. www.analog.com Tel: 781.329.4700 Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved. 6B21 GENERAL DESCRIPTION through an RS-485 port to exchange command and status information. An included EEPROM stores calibration constants as well as configuration information. The microcontroller also controls the output DAC through an optically-isolated serial interface. The D/A converter drives the current loop through a protective V/I (voltage-to-current) converter. The output monitor is a V/F converter whose frequency is proportional to the loop current. This variable signal frequency is fed back to the microcontroller through an optical isolator. The microcontroller then scales the frequency signal and returns the current read-back data to the host computer. A DC/DC converter generates 25 VDC from the +5 VDC power supply to power the current loop and output circuitry. The 6B21 is a single-channel signal-conditioning module which provides a digitally-controlled isolated current loop output to a resolution of 12 bits. The output range can be selected to either a 0 to 20 mA or 4 mA to 20 mA process current. It is electrically and mechanically compatible with the 6B Series input modules and backplanes. The 6B21 takes a command from the host computer and converts it into an isolated process current suitable for interfacing with valves and actuators. The 6B21 offers a normal mode output protection of 240 V rms as well as 1500 V rms CMV isolation. In addition the actual current flowing in the current loop is read back by an on-board isolated V/F (voltage-to-frequency) converter. The 6B21 can be software-configured for address, output range, baud rate, data format, checksum status, slew rate, and start-up value. All programmable parameters are stored in the nonvolatile memory of the module. An on-board microcontroller communicates with the host . . Figure 2 Rev. 0 | Page 2 of 8 6B21 Model 6B21 Range Description (Software Configurable) Accuracy (Typical) Accuracy (Maximum) 0 mA to 20 mA ±0.02 % FSR ±0.05 % FSR 4 mA to 20 mA ±0.02 % FSR ±0.05 %FSR 6B21 Specifications (typical @ +25°C and Vs = +5 V dc) Description Model 6B21 Output, Software Selectable Current, Operating Ranges 0 mA to 20 mA or 4 mA to 20 mA Current, Over-range +2 mA ±200 µA Load Resistance 0 to 750 Ω Communications Protocol RS-485 Baud Rates, Software selectable 300K, 600K, 1.2K, 2.4K. 9.6K, 19.2K Output Current Initial Accuracy Output Offset ±5 µA (±15 µA maximum) Span ±0.02% Full Scale Range (±0.05%, max.) Accuracy vs. Temperature Output Offset Current ±1 µA°C Gain ±50 ppm/°C Resolution ±0.02% Full Scale Range Nonlinearity ±0.02% Full Scale Range Output Noise, 0.1 Hz to 100 Hz Bandwidth 1 µA peak-to-peak Bandwidth, -3 dB 3 Hz Conversion Rate 100 samples/second Setting Time 1 ms to ±0.1% Full Scale Range Output Slew Rate Software Selectable (11 Binary Ranges) 0.125 mA/sec to 128 mA/sec Common-Mode Voltage (CMV) Output-to-Input and Power 1500 V rms continuous Common Mode Rejection (CMR) Output-to-Input and Power @60 Hz 108 dB Output Protection 240 V rms, continuous Output Transient Protection ANSI/IEEE C37.90.1-1989 Rev. 0 | Page 3 of 8 6B21 Output Readback Initial Accuracy @ +25°C Output Offset Current ±100 µA Span ±0.5% Full Scale Range Accuracy vs Temperature Output Offset Current ±5 µA/°C Gain ±200 ppm/°C Resolution ±0.5% Full Scale Range Nonlinearity ±0.5% Full Scale Range Power Supply Voltage, Operating +5 V dc ±5% Voltage, maximum safe limit +6.5 V dc Current +250 mA Mechanical Dimensions 2.3" x 3.1" x 0.79" (58.4 mm x 78.7 mm x 19.1 mm) Environmental Temperature Range Rated Performance -25°C to +85°C Operating -25°C to +85°C Storage -40°C to +85°C Relative Humidity 0 to 95% @ +60°C, non-condensing Specifications subject to change without notice. Rev. 0 | Page 4 of 8 6B21 PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS Figure 3 . Model 6B Series Module, with pin-out assignments. Table 1. Pin Function Descriptions— Pin No. 1 2 3 4 Description N/C HI LO N/C Figure 4 6B21Input Field Connections ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Rev. 0 | Page 5 of 8 6B21 OUTLINE DIMENSIONS Figure 5. Outline Dimensions Rev. 0 | Page 6 of 8 6B21 NOTES Rev. 0 | Page 7 of 8 6B21 NOTES © 2004 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective companies. D05166-0-9/04(0) Rev. 0 | Page 8 of 8