National Instruments SCXI-1121 Calibration Procedure page 15

Adjusting the Module
© National Instruments Corporation
If you do not have a terminal block, refer to Figure 3 for connection
information.
4. Compare the DMM reading to the limits for excitation shown in
Table 9. If the reading falls between the Upper Limit and Lower Limit
values, the module passed the test.
Table 9. SCXI-1121 Current Excitation Limits
Test Point (mA)
0.150
0.450
5. Configure the channel for 0.450 mA excitation level and repeat
steps 2 and 4.
6. Repeat steps 2 through 5 for all remaining channels.
You have completed verifying the current excitation limits. If any of your
measurements fall outside the specifications listed in Table 9, adjust the
module as described in the
This section contains adjustment procedures for the analog input offsets,
the voltage excitation limits, and the current excitation limits. Refer to the
Setting Up the Module
channel gain, channel filter, and excitation level.
Adjusting Analog Input Offsets
Complete the following steps to adjust the offset null value:
1. Set the channel gain on the channel you are adjusting to a gain of 1.
Set the filter value to 4 Hz.
2. Connect the calibrator to the analog input channel you want to adjust.
Refer to Table 7 to determine the pins on the 96-pin front connector
that correspond to the positive and negative inputs of the specified
channel. For example, the positive input for channel 0 is pin A32,
which is labeled CH0+. The negative input for channel 0 is pin C32,
which is labeled CH0–.
3. Set the DMM to voltage mode, and connect it to the output of the same
channel to which the calibrator was connected in step 2. Refer to
Figure 4 to determine the pins on the 50-pin rear connector that
corresponds to the positive and negative outputs for the specified
channel. For example, the positive output for channel 0 is pin 3, which
is labeled MCH0+. The negative output for channel 0 is pin 4, which
is labeled MCH0–.
Upper Limit (mA)
0.150060
0.450900
Adjusting Current Excitation
section for information on how to configure the
15
Lower Limit (mA)
0.149940
0.449100
section.
SCXI-1121 Calibration Procedure