National Instruments SCXI-1121 Manuel D’Utilisation

This procedure calibrates the 10 V and 450 µA levels at the same time but 
the accuracy achieved is limited to ±0.2%. To achieve better accuracies at 
these levels, follow the procedure indicated above but set the excitation 
levels to 10 V and to 450 µA instead of 3.333 V and 150 µA. If you do so, 
the lower excitation levels of this channel will then be calibrated to ±0.2% 
instead of to 0.04%. In the factory, the module is calibrated for 3.333 V and 
150 µA.

You can seal the potentiometers after calibration with antisabotage lacquer 
to avoid tampering with the calibration.

Table 3-2 lists the potentiometer reference designators that correspond to 
each channel.

The resistor used to calibrate the current level must be a precision type with 
a tempco of 5 ppm or less. You should measure and record the resistor value 
before each calibration procedure. The DMM you are using should provide 
you with the required resolution and accuracy to achieve the calibration 
levels indicated in the paragraphs above. Annual or semi-annual calibration 
is recommended to maintain the accuracy level.

Table 3-2.  Calibration Potentiometer Reference Designators

0

R2

R3

R10

R7

1

R16

R4

R20

R17

2

R26

R5

R30

R27

3

R36

R6

R40

R37