National Instruments SCXI-1141 Calibration Procedure
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CALIBRATION PROCEDURE
SCXI -1141/1142/1143
Conventions
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This document contains the information and instructions needed to
calibrate the SCXI-1141/1142/1143 using Traditional NI-DAQ (Legacy).
Calibrate the SCXI-1141/1142/1143 at a regular interval as defined by the
measurement accuracy requirements of your application. NI recommends
performing a complete calibration at least once every year. Based on your
measurement accuracy needs, you can shorten this interval to 90 days or
six months.
The following conventions apply to this document:
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Summary of Contents for National Instruments SCXI-1141

  • Page 1 This document contains the information and instructions needed to calibrate the SCXI-1141/1142/1143 using Traditional NI-DAQ (Legacy). Calibrate the SCXI-1141/1142/1143 at a regular interval as defined by the measurement accuracy requirements of your application. NI recommends performing a complete calibration at least once every year. Based on your measurement accuracy needs, you can shorten this interval to 90 days or six months.
  • Page 2 /CVI Microsoft Visual C++, Microsoft Visual Basic, and Borland C++. If the SCXI-1141/1142/1143 is revision F or later, this procedure requires using a calibration software library. The library contains a function that is needed to adjust calibration circuitry on the module. If you do not have the...
  • Page 3: Test Equipment

    SCXI-1141/1142/1143 User Manual. Test Equipment NI recommends using the equipment in Table 1 to verify and calibrate the SCXI-1141/1142/1143. If these instruments are not available, use the accuracy requirements listed to select a suitable substitute. Table 1. Test Equipment...
  • Page 4: Test Conditions

    Adjusting the offset and gain errors using a known external voltage source. Verifying that the SCXI-1141/1142/1143 is operating within its test limits after adjustments. Setting up the SCXI-1141/1142/1143 for Calibration Complete the following steps, while referring to Figure 1 to set up the SCXI-1141/1142/1143 for calibration.
  • Page 5 12 DAQ Device Figure 1. Typical SCXI-1141/1142/1143 Setup for Calibration Verifying the Operation of the SCXI-1141/1142/1143 The verification procedure determines how well the SCXI-1141/1142/1143 is meeting its specifications. You can use this information to select the appropriate calibration interval for your application.
  • Page 6: Verifying Analog Input Measurements

    SCXIchassisID—The value obtained from MAX • moduleSlot—1 • moduleChan—0 • gain—The gain value from Table 9 that you want to test Call to disable the filter. SCXI_Configure_Filter Set the following parameters: • SCXIchassisID—The value obtained from MAX SCXI-1141/1142/1143 Calibration Procedure ni.com...
  • Page 7 13. Repeat steps 6 through 12 for each remaining test point. 14. Repeat steps 6 through 13 for each remaining channel, changing the moduleChan variable to the channel number you are testing. You have finished verifying the operation of the SCXI-1141/1142/1143. © National Instruments Corporation SCXI-1141/1142/1143 Calibration Procedure...
  • Page 8: Verifying Filter Parameters

    Verifying Filter Parameters Complete the following steps to set up the SCXI-1141/1142/1143 for this verification process: Read the Test Conditions section in this document. Ensure that the E Series DAQ device is connected to the SCXI-1141/1142/1143. Call to enable the cutoff filter.
  • Page 9 Verify that the DMM output is within the bounds specified by Tables 4, 5, or 6. Repeat steps 1 and 2 until all test points are verified. Table 4. Passband Test Points for the SCXI-1141 Frequency (kHz) Lower Limit (V Upper Limit (V 5.94...
  • Page 10: Measuring Gain Errors

    Frequency (kHz) Lower Limit (V Per Limit (V 0.9882 1.0119 Adjusting the SCXI-1141/1142/1143 This section contains three adjustment procedures: one for measuring gain error, one for adjusting calibration gain constants, and one for adjusting filter AC gain. Measuring Gain Errors...
  • Page 11 If you are using an SCXI-1304 connected to the SCXI-1141/1142/1143, connect the calibrator to the AI 0 + and AI 0 – inputs and verify that the SCXI-1304 is set to DC coupling.
  • Page 12: Adjusting Calibration Constants

    You have finished measuring the gain on the SCXI-1141/1142/1143. Adjusting Calibration Constants Complete the following steps to adjust the calibration constants on the SCXI-1141/1142/1143 to compensate for the gain error measured in the Measuring Gain Errors section: Reconnect the E Series DAQ device to the SCXI-1141/1142/1143.
  • Page 13: Adjusting Filter Ac Gain

    500 Hz. SCXI-1141/1142/1143 Before Revision F Complete the following steps to set up the SCXI-1141/1142/1143 for adjustment and to adjust the AC gain filter, referring to Figures 2 and 3 as needed: Remove the grounding screw from the module.
  • Page 14 Set the following parameters: • SCXIchassisID—The device number assigned by MAX • moduleSlot—4 • moduleChan—0 • gain—1 Call to enable the filter bypass. Set the SCXI_Configure_Filter following parameters: • SCXIchassisID—The value configured in MAX • moduleSlot—40 • channel—0 SCXI-1141/1142/1143 Calibration Procedure ni.com...
  • Page 15 96-pin front connector that correspond to the positive and negative inputs of the specified channel. If you are using an SCXI-1304 connected to the SCXI-1141/1142/1143, connect the calibrator to the AI 0 + and AI 0 – inputs.
  • Page 16 96-pin front connector that correspond to the positive and negative inputs of the specified channel. If you are using an SCXI-1304 that is connected to the SCXI-1141/1142/1143, connect the calibrator to the AI 0 + and AI 0 – inputs.
  • Page 17: Verifying Adjusted Values

    If the module fails verification after adjustment, return it to NI for repair or Note replacement. Front and Rear Panel Pin Assignments Table 7 shows the pin assignments for the SCXI-1141/1142/1143 front panel connector. © National Instruments Corporation SCXI-1141/1142/1143 Calibration Procedure...
  • Page 18 AI 5 – A GND A GND AI 6 + AI 6 – AI 7 + AI 7 – RSVD RSVD RSVD RSVD RSVD EXT CLK NC means no connection. D GND OUT CLK RSVD means reserved. SCXI-1141/1142/1143 Calibration Procedure ni.com...
  • Page 19 Table 8 shows the pin assignments for the SCXI-1141/1142/1143 rear panel connector. Table 8. Rear Signal Pin Assignments Rear Connector Diagram Signal Name Pin Number Pin Number Signal Name AI 0 + AI 0 – AI 1 + A GND...
  • Page 20: Specifications

    Instruments trademarks. Other product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your CD, or ni.com/patents.

This manual is also suitable for:

Scxi-1142Scxi-1143

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