INSTALLATION GUIDE SCXI -1313A Terminal Block ™ This guide describes how to install and use the SCXI-1313A terminal block with an SCXI-1125 module. The SCXI-1313A terminal block is shielded and has screw terminals that provide input connections for the SCXI-1125. Each SCXI-1313A channel has a precision 100:1 resistive voltage divider that you can use to measure voltages of up to 150 Vrms or ±150 VDC. You can individually bypass these voltage dividers for low-voltage measurement applications. The terminal block has 18 screw terminals for easy signal connection. One pair of screw terminals connects to the SCXI-1125 chassis ground. The remaining eight pairs of screw terminals connect signals to the eight analog inputs. Conventions The following conventions are used in this guide: » The » symbol leads you through nested menu items and dialog box options to a final action. The sequence File»Page Setup»Options directs you to pull down the File menu, select the Page Setup item, and select Options from the last dialog box. This icon denotes a note, which alerts you to important information. This icon denotes a caution, which advises you of precautions to take to avoid injury, data loss, or a system crash. When this symbol is marked on a product, refer to the Read Me First: Safety and Radio-Frequency Interference for information about precautions to take. When symbol is marked on a product, it denotes a warning advising you to take precautions to avoid electrical shock. When symbol is marked on a product, it denotes a component that may be hot. Touching this component may result in bodily injury. bold Bold text denotes items that you must select or click in the software, such as menu items and dialog box options. Bold text also denotes parameter names. italic Italic text denotes variables, emphasis, a cross-reference, or an introduction to a key concept. Italic text also denotes text that is a placeholder for a word or value that you must supply. monospace Text in this font denotes text or characters that you should enter from the keyboard, sections of code, programming examples, and syntax examples. This font is also used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, functions, operations, variables, filenames, and extensions. monospace italic Italic text in this font denotes text that is a placeholder for a word or value that you must supply. What You Need to Get Started To set up and use the SCXI-1313A terminal block, you need the following items: ❑ Hardware – SCXI-1313A terminal block – SCXI-1125 module – SCXI or PXI/SCXI combination chassis – Cabling and sensors as required for your application ❑ Tools – Number 1 and 2 Phillips-head screwdrivers – 1/8 in. flathead screwdriver – Long-nose pliers – Wire cutter – Wire insulation stripper ❑ Documentation – SCXI-1313A Terminal Block Installation Guide – Read Me First: Safety and Radio-Frequency Interference – DAQ Getting Started Guide – SCXI Quick Start Guide – SCXI-1125 User Manual – SCXI chassis or PXI/SCXI combination chassis user manual You can download needed documents from ni.com/manuals. SCXI-1313A Terminal Block Installation Guide 2 ni.com Connecting Signals Note Refer to the Read Me First: Safety and Radio-Frequency Interference document before removing equipment covers or connecting or disconnecting any signal wires. To connect the signal to the terminal block, refer to Figures 1 and 2 while completing the following steps: 10 9 WA RN IN G: 7 1 6 8 2 5 3 4 Back View 1 2 3 4 Front View Top Cover Screws Top Cover Terminal Block Enclosure Thumbscrew (2) 5 6 7 Rear Connector Circuit Board Safety-Ground Lug 8 Circuit Board Attachment Screws 9 Strain-Relief Bar 10 Strain-Relief Screws Figure 1. SCXI-1313A Parts Locator Diagram 1. Unscrew the top cover screws and remove the top cover. 2. Loosen the strain-relief screws and remove the strain-relief bar. 3. Prepare the signal wire by stripping the insulation no more than 7 mm (0.28 in.). © National Instruments Corporation 3 SCXI-1313A Terminal Block Installation Guide 4. Run the signal wires through the strain-relief opening. If necessary, add insulation or padding. 5. Insert the stripped end of the signal wires fully into the terminal. Make sure no exposed wire extends past the screw terminal. Exposed wire increases the risk of a short circuit that can cause circuit failure. 1 2 3 9 8 1 2 3 4 5 6 7 5 Serial Number Assembly Number and Revision Letter Relays to Enable or Bypass the Attenuator (8 places) Chassis Ground Terminal (2 places) Product Name 4 6 7 8 9 Thermistor Screw Terminal (16 places) Channel Labeling (8 places) Voltage Divider (8 places) Figure 2. SCXI-1313A Circuit Board Parts Locator Diagram 6. Tighten the terminal screws to a torque of 0.57 to 0.79 N ⋅ m (5 to 7 lb - in.). 7. Reinstall the strain-relief bar and tighten the strain-relief screws. 8. Reinstall the top cover and tighten the top cover screws. 9. Attach the SCXI-1313A to the SCXI-1125 using the thumbscrews. 10. Refer to the SCXI Quick Start Guide to power on the SCXI chassis and configure the system in software. For accurate cold-junction compensation, place the chassis away from an extreme temperature differential. Note SCXI-1313A Terminal Block Installation Guide 4 ni.com Configuring the High-Voltage Attenuator Each channel has a 100:1 high-voltage attenuator. To enable or disable the attenuator, either change the default configuration settings for the SCXI-1313A in Measurement & Automation Explorer (MAX) or adjust the input limit ranges in your application. When using virtual channels, the input limits configured in the virtual channel configurator are used to set the attenuation circuitry appropriately. SCXI-1313 is the designator for both the SCXI-1313 and SCXI-1313A in MAX and NI-DAQ. Note The calibration EEPROM on the SCXI-1313A stores calibration constants that provide software correction values. These values are used by the application development software to correct the measurements for gain errors in the attenuation circuitry. Table 1. Input Signal Range Versus Gain Overall Gain © National Instruments Corporation Overall Voltage Range1 Module Gain Terminal Block Gain 0.02 ±150 Vrms or ±150 VDC 2 0.01 0.05 ±100 Vpeak or ±100 VDC 5 0.01 0.1 ±50 Vpeak or ±50 VDC 10 0.01 0.2 ±25 Vpeak or ±25 VDC 20 0.01 0.5 ±10 Vpeak or ±10 VDC 50 0.01 1 ±5 Vpeak or ±5 VDC 1 1 2 ±2.5 Vpeak or ±2.5 VDC 2 1 2.5 ±2 Vpeak or ±2 VDC 250 0.01 5 ±1 Vpeak or ±1 VDC 5 1 10 ±500 mVpeak or ±500 mVDC 10 1 20 ±250 mVpeak or ±250 mVDC 20 1 50 ±100 mVpeak or ±100 mVDC 50 1 100 ±50 mVpeak or ±50 mVDC 100 1 200 ±25 mVpeak or ±25 mVDC 200 1 250 ±20 mVpeak or ±20 mVDC 250 1 5 SCXI-1313A Terminal Block Installation Guide Table 1. Input Signal Range Versus Gain (Continued) Overall Gain 1 Overall Voltage Range1 Module Gain Terminal Block Gain 500 ±10 mVpeak or ±10 mVDC 500 1 1000 ±5 mVpeak or ±5 mVDC 1000 1 2000 ±2.5 mVpeak or ±2.5 mVDC 2000 1 Refer to the Specifications section for the input range. Calibrating the Terminal Block Most external calibration documents for SCXI product are available to download from ni.com/calibration by clicking Manual Calibration Procedures. For external calibration of products not listed there, Basic Calibration Service or Detailed Calibration Service is recommended. You can get information about both of these calibration services at ni.com/calibration. NI recommends performing an external calibration once a year. Temperature Sensor Output and Accuracy The SCXI-1313A temperature sensor outputs 1.91 to 0.65 V from 0 to 50 °C. Converting a Thermistor Voltage to a Temperature NI software can convert a thermistor voltage to the thermistor temperature for the circuit diagram shown in Figure 3. In LabVIEW, you can use the Convert Thermistor Reading VI found in the Data Acquisition»Signal Conditioning palette. If you are using CVI or NI-DAQmx, use the Thermistor_Convert function. The VI takes the output voltage of the temperature sensor, the reference voltage, and the precision resistance and returns the thermistor temperature. Alternatively, you can use the following formulas: T(°C ) = T K – 273.15 SCXI-1313A Terminal Block Installation Guide 6 ni.com where TK is the temperature in Kelvin 1 T K = -------------------------------------------------------------3 [ a + b ( ln R T ) + c ( ln R T ) ] a = 1.295361 × 10 –3 b = 2.343159 × 10 –4 c = 1.018703 × 10 –7 RT = resistance of the thermistor in ohms V TEMPOUT ⎞ R T = 5,000 ⎛ ------------------------------------⎝ 2.5 – V TEMPOUT⎠ VTEMPOUT = output voltage of the temperature sensor [ T ( °C ) ]9 T ( °F ) = ----------------------- + 32 5 where T(°F) and T(°C) are the temperature readings in degrees Fahrenheit and degrees Celsius, respectively. Note Use an average of a large number of samples to obtain the most accurate reading. Noisy environments require more samples for greater accuracy. Reading the Temperature Sensor in LabVIEW In LabVIEW, to read VTEMPOUT, use NI-DAQmx with the following string: SC(x)Mod(y)/_cjTemp To read VTEMPOUT with Traditional NI-DAQ (Legacy), use the address string: obx ! scy ! mdz ! cjtemp You can have this channel-address string in the same channel-string array as other channels on the same SCXI-1125 module and call it multiple times within the same channel-string array. For more information about channel-string arrays and the SCXI channel-addressing syntax, see the LabVIEW Measurements Manual. © National Instruments Corporation 7 SCXI-1313A Terminal Block Installation Guide Temperature Sensor Circuit Diagram You do not need to read this section to operate the SCXI-1313A. The circuit diagram in Figure 3 is optional information that you can use if you want more details about the SCXI-1313A temperature sensor. +5 V 2.5 V 2 LM 4040 2.5 V 0.1% 0.1 µF –t o MTEMP + 1 10 µF 2 16 V 1 2 0.1 µF Figure 3. Temperature Sensor Circuit Diagram Specifications All specifications are typical at 25 °C unless otherwise specified. Input range ..............................................150 Vrms or VDC Measurement category............................CAT II Input channels.........................................8 Cold-junction sensor Sensor type ......................................Thermistor Accuracy1 ........................................±0.5 °C from 15 to 35 °C ±0.9 °C from 0 to 15 °C and 35 to 55 °C Repeatability....................................±0.2 °C from 15 to 35 °C 1 The temperature sensor accuracy includes tolerances in all component values, effects caused by temperature and loading, and self-heating. Errors caused by temperature gradients between terminals and the sensor are not included in this specification. SCXI-1313A Terminal Block Installation Guide 8 ni.com Output ............................................. 1.91 to 0.65 V from 0 to 50 °C Maximum temperature gradient between sensor and any terminal .... ±0.4 °C (non-isothermal) High-voltage divider Accuracy ................................................ ±0.06% (for 100:1 setting) Drift................................................. 15 ppm/°C Resistance ....................................... 1 MΩ Attenuation ratio ............................. 100:1 or 1:1 on programmatic basis Common-mode isolation Channel to channel.......................... 150 Vrms or ±150 VDC Channel to ground........................... 150 Vrms or ±150 VDC Coupling.......................................... DC only Field-wiring connectors Screw terminals Signal terminals ....................... 16 (8 pairs) Functional ground terminals .... 2 Maximum wire gauge .............. 16 AWG Terminal spacing ..................... 0.5 cm (0.2 in.) center-to-center Dimensions of front entrance.......... 1.2 × 7.3 cm (0.47 × 2.87 in.) Solder pads for additional components .................... None Safety earth-ground lugs ................. 1 Strain relief ..................................... Strain-relief bar at terminal-block entrance Maximum working voltage.................... 150 V © National Instruments Corporation 9 SCXI-1313A Terminal Block Installation Guide Physical 30.3 mm (1.19 in.) 82.5 mm (3.25 in.) NATIONAL INSTRUMENTS 173.5 mm (6.83 in.) Figure 4. SCXI-1313A DImensions Weight ....................................................408 g (14.4 oz) Environment Operating temperature ............................0 to 50 °C Storage temperature ................................–20 to 70 °C Humidity .................................................10 to 90% RH, noncondensing Maximum altitude...................................2,000 meters Pollution Degree (indoor use only) ........2 SCXI-1313A Terminal Block Installation Guide 10 ni.com Safety This product is designed to meet the requirements of the following standards of safety for electrical equipment for measurement, control, and laboratory use: • IEC 61010-1, EN 61010-1 • UL 61010-1, CSA 61010-1 Note For UL and other safety certifications, refer to the product label or visit ni.com/ certification, search by model number or product line, and click the appropriate link in the Certification column. Electromagnetic Compatibility This product is designed to meet the requirements of the following standards of EMC for electrical equipment for measurement, control, and laboratory use: Note • EN 61326 EMC requirements; Minimum Immunity • EN 55011 Emissions; Group 1, Class A • CE, C-Tick, ICES, and FCC Part 15 Emissions; Class A For EMC compliance, operate this device according to product documentation. CE Compliance This product meets the essential requirements of applicable European Directives, as amended for CE marking, as follows: • 2006/95/EC; Low-Voltage Directive (safety) • 2004/108/EC; Electromagnetic Compatibility Directive (EMC) Refer to the Declaration of Conformity (DoC) for this product for any additional regulatory compliance information. To obtain the DoC for this product, visit ni.com/ certification, search by model number or product line, and click the appropriate link in the Certification column. 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