© National Instruments Corporation 5-1 SC-2043-SG User Manual
Chapter 5Calibration Procedures

This chapter discusses the calibration procedures for the SC-2043-SG board.

Excitation Adjustment

Onboard Excitation Source

The excitation voltage source on the SC-2043-SG is factory-adjusted to 2.5 V ±0.5%. This
circuit has one potentiometer (R2) that you must adjust to change the excitation voltage level on
all eight output channels.
Note: Because the offset nulling circuitry uses the excitation voltage as a reference, if you
want to change the excitation voltage level or you are using external excitation, you
MUST complete your excitation voltage level adjustments before adjusting the offset
nulling circuitry. If you do not, you will have to readjust the offset nulling voltage
levels on all channels.
If you want to readjust the onboard excitation voltage level to a different value, you must
perform the following steps:
1. If you are using a rack-mount kit, remove the cover to expose the calibration pot.
2. Configure all your strain gauge bridges to the desired SC-2043-SG channels so that the
excitation voltage source is calibrated with the exact bridge load it must supply. Refer to
Chapter 3, Signal Connections, for more information.
Note: Remember to short the input terminals (CHn
±
) of any unused channel to its
negative excitation output terminal (-EXn).
3. Select and read the channel that is configured for local excitation sensing. If you have not
configured the SC-2043-SG for local excitation sensing, refer to Chapter 2, Installation and
Configuration, for more information.
4. Adjust the potentiometer (R2) wiper with a flathead screwdriver until the voltage you are
monitoring reaches the exact level desired.
5. Replace the rack-mount chassis cover, if used.