Справочник Пользователя для National Instruments 321645c-01

Chapter 2

Function Reference — SCXI_Calibrate_Setup

NI-DAQ FRM for PC Compatibles

2-330

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 National Instruments Corporation

Used to ground the amplifier inputs of an SCXI-1100, SCXI-1122, or SCXI-1141 so that you 
can determine the amplifier offset. You can also use this function to switch a shunt resistor 
across your bridge circuit to test the circuit. Shunt calibration is supported for the SCXI-1122 
or SCXI-1121 modules with the SCXI-1321 terminal block.

calOp indicates the calibration mode you want.

0:

Disable calibration.

1:

Connect the positive and negative inputs of the SCXI-1100, SCXI-1122, 
or SCXI-1141 amplifier together and to analog reference.

2:

Switch the shunt resistors across the bridge circuit on the SCXI-1121 
(Revision C or later) or SCXI-1122.

The zero offset of the SCXI-1100, SCXI-1122, or SCXI-1141 amplifiers varies with the 
module gain. When you know the offset at a specific gain setting, you can add that offset to 
any readings acquired at that gain. In general, the procedure for determining the offset at a 
particular gain is as follows:

1.

SCXI_Single_Chan_Setup

—Enable the module output, route the module output 

on the SCXIbus if necessary, and resolve any SCXIbus contention if necessary. For 
the SCXI-1100 and SCXI-1122, the module channel you specify is irrelevant.

2.

SCXI_Set_Gain

—Set the module gain to the setting that you will use in your 

application.

3.

SCXI_Calibrate_Setup

—Ground the amplifier inputs.

i16

logical ID assigned to the SCXI chassis

i16

chassis slot number

i16

calibration mode