National Instruments SCXI-1121 Manuel D’Utilisation

© National Instruments Corporation

To measure one of the four differential input channels to the SCXI-1121, 
perform the following steps:

1.

Write the binary pattern 

000XXXCC XX000000

 to the SCXI-1121 

Configuration Register.

2.

Measure the voltage with the data acquisition board.

To shunt calibrate one of the four differential input channels, perform the 
following steps:

1.

Write the binary pattern 

001XXXCC XX00000

 to the SCXI-1121 

Configuration Register. Insert a delay of at least 1 sec if you have set 
the 4 Hz filter, or at least 1 msec if you have set the 10 kHz filter. This 
delay permits the SCXI-1121 amplifier to settle.

2.

Measure the voltage with the data acquisition board.

To measure the voltage on the MTEMP line, perform the following steps:

1.

Write the binary pattern 

000XXXXX XX100000

 to the SCXI-1121 

Configuration Register.

2.

Measure the voltage with the data acquisition board.

Indirect measurements involve one module sending a signal to Analog 
Bus 0, where it is picked up by another module and transmitted to the data 
acquisition board.

To perform measurements from other modules, you must cable the 
SCXI-1121 rear signal connector to a data acquisition board. See 
Chapter 2, 

, for more information. To make 

a measurement from another module, perform the following steps:

1.

Perform any necessary programming to ensure that no modules are 
driving Analog Bus 0. For an SCXI-1121, clearing AB0EN in the 
Configuration Register will ensure that its output is not driving AB0.

2.

Write the binary pattern 

000XXXXX XX100011

 to the SCXI-1121 

Configuration Register. This step disables the SCXI-1121 from driving 
Analog Bus 0 and allows Analog Bus 0 to drive MCH0 through the 
output buffer.

3.

Program the other module to drive Analog Bus 0 with the signal to be 
measured.

4.

Measure the voltage with the data acquisition board.