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7

SCXI-1125 Calibration Procedure

Complete the following steps to verify the accuracy of each SCXI-1125 
analog input channel:

1.

Use the DAQmx Self Calibrate VI to verify the DAQ device. This VI 
measures the onboard reference voltage of the DAQ device and adjusts 
the self-calibration constants to account for any errors caused by 
short-term fluctuations in the operating environment.

Note

Throughout the verification procedure, refer to the function call parameters for the 

LabVIEW input values.

2.

Connect the calibrator output to pins AI- and AI+ for all channels. 
Refer to the 

SCXI-1320 High-Voltage Terminal Block Installation 

Guide and Specifications

 for connection instructions. If you are not 

using the recommended SCXI-1320, refer to Table 4 for the front 
signal pin assignments of the SCXI-1125. If the calibration signal 
source is floating, connect AI- to the SCXI chassis ground using the 
ground lug available on the SCXI terminal block.

3.

Set the calibrator voltage to the desired test point indicated in Table 2.

4.

Create a task using 

DAQmxCreateTask

.

LabVIEW Block Diagram

NI-DAQmx Function Call

Call 

DAQmxSelfCal

 with the following 

parameter:

deviceName

: "

Dev1

"

LabVIEW Block Diagram

NI-DAQmx Function Call

LabVIEW does not require this step.

Call 

DAQmxCreateTask

 with the following 

parameters:

taskName

: "

AIVerificationTask

"

taskHandle

&taskHandle

Содержание Module SCXI-1125

Страница 1: ...rocedure 5 Adjustment Procedure 10 Verifying Adjusted Values 12 Test Limits 13 Gain and Offset 13 SCXI 1125 Front and Rear Panel Diagrams 15 World Wide Support and Services 18 Conventions The followin...

Страница 2: ...are The SCXI 1125 calibration procedure requires the NI DAQmx driver NI recommends using the latest driver that supports both your development environment and the SCXI 1125 NI DAQmx includes high leve...

Страница 3: ...itions Follow these guidelines to optimize the connections and the environment during calibration Keep connections to the SCXI 1125 as short as possible Long cables and wires can act as antennas picki...

Страница 4: ...ment Procedure Perform an external calibration that adjusts the SCXI 1125 calibration constants with respect to a known voltage source 4 Verifying Adjusted Values Perform another verification to ensur...

Страница 5: ...u configure a device in MAX the device is assigned a device identifier In this calibration document the functions used for demonstrating the calibration process use the device identifiers Dev1 for the...

Страница 6: ...set calibration constants for each gain setting per analog input channel A complete verification of the inputs involves measuring the accuracy at all possible gain settings on all channels of the SCXI...

Страница 7: ...annels Refer to the SCXI 1320 High Voltage Terminal Block Installation Guide and Specifications for connection instructions If you are not using the recommended SCXI 1320 refer to Table 4 for the fron...

Страница 8: ...ed Gain LabVIEW Block Diagram NI DAQmx Function Call Call DAQmxCreateAIVoltageChan with the following parameters taskHandle taskHandle physicalChannel SC1Mod1 aiX nameToAssignToChannel myVoltageChanne...

Страница 9: ...VIEW Block Diagram NI DAQmx Function Call Call DAQmxCfgSampClkTiming with the following parameters taskHandle taskHandle source rate 1000 0 activeEdge DAQmx_Val_Rising sampleMode DAQmx_Val_FiniteSamps...

Страница 10: ...points in Table 2 You have finished verifying the analog input accuracy of the SCXI 1125 Adjustment Procedure The adjustment procedure adjusts the gain and offset calibration constants on the SCXI 112...

Страница 11: ...ents of the SCXI 1125 If the calibration signal source is floating connect AI to the SCXI chassis ground using the ground lug available on the SCXI terminal block 3 Start an external calibration sessi...

Страница 12: ...is step 10 Repeat steps 3 through 9 for all gain values in Table 3 11 Repeat steps 2 through 10 for the remaining channels You have finished adjusting the gain and offset of the SCXI 1125 Verifying Ad...

Страница 13: ...n Table 2 do not include DAQ device errors Table 2 Upper and Lower Limit Channel Settings Gain Range Test Point Upper Limit V Lower Limit V 1 5 4 950000 4 982047 4 917953 1 0 0 000000 0 006802 0 00680...

Страница 14: ...89 0 009811 500 0 0 000000 0 000038 0 000038 500 0 01 0 009900 0 009811 0 009989 1000 0 005 0 00495 0 005007 0 004893 1000 0 0 000000 0 000031 0 000031 1000 0 005 0 004950 0 004893 0 005007 2000 0 002...

Страница 15: ...nts Gain Set Points V 1 4 5 3 1 5 0 1 5 3 4 5 2 2 25 1 5 0 75 0 0 75 1 5 2 25 5 0 9 0 6 0 3 0 0 3 0 6 0 9 10 0 45 0 3 0 15 0 0 15 0 3 0 45 20 0 225 0 15 0 075 0 0 075 0 15 0 225 50 0 09 0 06 0 03 0 0...

Страница 16: ...no connection no pin 32 AI 0 AI 0 31 30 AI 1 AI 1 29 28 NC NC 27 26 AI 2 AI 2 25 24 AI 3 AI 3 23 22 NC NC 21 20 AI 4 AI 4 19 18 AI 5 AI 5 17 16 NC NC 15 14 AI 6 AI 6 13 12 AI 7 AI 7 11 10 NC NC 9 8 R...

Страница 17: ...2 7 8 AO 2 AO 3 9 10 AO 3 AO 4 11 12 AO 4 AO 5 13 14 AO 5 AO 6 15 16 AO 6 AO 7 17 18 AO 7 OUT REF 19 20 21 22 23 24 D GND SER DAT IN 25 26 SER DAT OUT DAQ D A 27 28 SLOT 0 SEL 29 30 31 32 D GND 33 34...

Страница 18: ...et forth in FAR 52 227 14 DFAR 252 227 7014 and DFAR 252 227 7015 2000 2015 National Instruments All rights reserved 370271B 01 Oct15 World Wide Support and Services The National Instruments website i...

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