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SCXI-1141/1142/1143 Calibration Procedure

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Test Conditions

Follow these guidelines to optimize the connections and the environment 
during calibration:

Keep connections to the SCXI terminal block and the rear connector of 
the SCXI module short. Long cables and wires act as antennae, picking 
up extra noise and thermal offsets that can affect measurements.

Use shielded copper wire for all cable connections to the 
SCXI-1141/1142/1143. Use twisted-pair wire to reduce noise.

Maintain the temperature between 18 and 28 °C.

Keep relative humidity below 80%.

Allow a warm-up time of at least 15 minutes for the SCXI module and 
30 minutes for the DAQ device to ensure the measurement circuitry is 
at a stable operating temperature.

Calibration Procedure

This section provides step-by-step instructions for calling the appropriate 
calibration functions. 

The steps used in the calibration procedure are as follows:

1.

Setting up the SCXI-1141/1142/1143 for testing.

2.

Verifying the existing operation of the SCXI-1141/1142/1143 to 
determine whether it is operating within its test limits.

3.

Adjusting the offset and gain errors using a known external voltage 
source.

4.

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.

1.

Make sure all components involved in the calibration procedure are 
powered-off.

2.

Assemble the SCXI-1141/1142/1143, chassis, terminal block, and 
DAQ device as shown in Figure 1. The SCXI module you are 
calibrating must be connected directly to the DAQ device.

3.

Power on the SCXI chassis and the external computer.

4.

Make sure that all the appropriate driver and application software is 
installed.

Summary of Contents for SCXI-1141

Page 1: ...e 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 tip which alerts you to advisory in...

Page 2: ...acy which includes high level function calls to simplify the task of writing software to calibrate devices Traditional NI DAQ Legacy supports many programming languages including LabVIEW LabWindows CV...

Page 3: ...install Traditional NI DAQ Legacy After adding these help files you can access them by selecting Start Programs National Instruments NI DAQ Online DAQ Support The documents provide instructions about...

Page 4: ...calling the appropriate calibration functions The steps used in the calibration procedure are as follows 1 Setting up the SCXI 1141 1142 1143 for testing 2 Verifying the existing operation of the SCXI...

Page 5: ...w well the SCXI 1141 1142 1143 is meeting its specifications You can use this information to select the appropriate calibration interval for your application 1 SCXI 1304 Terminal Block 2 SCXI 1141 114...

Page 6: ...d by MAX calOp ND_SELF_CALIBRATE setOfCalConst ND_USER_EEPROM_AREA calRefVolts 0 0 5 Call MIO_Config to enable dithering on the E Series DAQ device measurements Set the following parameters DAQdeviceN...

Page 7: ...arameters SCXIChassisID The device number assigned by MAX moduleSlot 1 channel 0 SCXIgain The gain you are testing TBgain 1 DAQboard The device number for the DAQ device DAQChannel 0 DAQgain 1 numPoin...

Page 8: ...g input channel 0 Refer to Table 7 to determine which pins on the 96 pin front connector correspond to the positive and negative inputs of the specified channel If you are using an SCXI 1304 connected...

Page 9: ...et the calibrator output to a 1 Vrms sine wave at the frequency specified in Tables 4 5 or 6 2 Verify that the DMM output is within the bounds specified by Tables 4 5 or 6 3 Repeat steps 1 and 2 until...

Page 10: ...he SCXI 1141 1142 1143 4 Call SCXI_Single_Chan_Setup to configure the module for single channel measurements Set the following parameters SCXIchassisID The value obtained from MAX moduleSlot 1 moduleC...

Page 11: ...for later use 10 Set the calibrator to the negative test point value for the same gain Skip any input limits that are specified as 0 0 V You need only upper and lower limits for adjustment 11 Read th...

Page 12: ...slot channel The channel you want to adjust opCode 2 calibrationArea 0 rangeCode 0 not used for the SCXI 1141 1142 1143 SCXIgain The gain setting you want to adjust DAQboard The device number assigned...

Page 13: ...the sine wave must be lower than 1 50th of the cutoff frequency For this procedure in sections SCXI 1141 1142 1143 Before Revision F or SCXI 1141 1142 1143 Revision F or Later you will set the filters...

Page 14: ...E Series DAQ device is connected to the SCXI 1141 1142 1143 7 Call SCXI_Set_Gain to configure the module to a gain value of 1 Set the following parameters SCXIchassisID The device number assigned by M...

Page 15: ...channel 0 is pin 4 which is AI 0 11 Set the calibrator voltage to 3 4 Vrms 400 Hz 12 Measure and record the amplitude of the sine wave with the DMM 13 Call SCXI_Configure_Filter to disable the filter...

Page 16: ...nputs 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 6 Connect the DMM to the output of channel...

Page 17: ...MAX moduleSlot 4 channel 0 value The new value decided upon in step 12 14 Repeat steps 11 through 13 until the measured amplitude is as close as possible to the level it was with the filter in bypass...

Page 18: ...3 NC AI 3 23 NC NC NC 22 A GND NC A GND 21 NC NC NC 20 AI 4 NC AI 4 19 NC NC NC 18 AI 5 NC AI 5 17 NC NC NC 16 A GND NC A GND 15 NC NC NC 14 AI 6 NC AI 6 13 NC NC NC 12 AI 7 NC AI 7 11 NC NC NC 10 NC...

Page 19: ...GND AI 3 9 10 A GND AI 4 11 12 A GND AI 5 13 14 A GND AI 6 15 16 A GND AI 7 17 18 A GND NC 19 20 NC NC 21 22 NC NC 23 24 DIG GND SER DAT IN 25 26 SER DAT OUT DAQ D A 27 28 NC SLOT 0 SEL 29 30 NC NC 31...

Page 20: ...41 1142 1143 If the module has been calibrated within the last year the Test Point V value should fall between the Upper Limit V and Lower Limit V values Table 9 SCXI 1141 1142 1143 Specifications Tes...

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