National Instruments 24-Bit Half/Full-Bridge Analog Input Module NI 9237 - Manual (Page 8)

NI 9237 Operating Instructions and Specifications 8 ni.com
The NI 9237 has a four-terminal external excitation voltage source
connector. You can use the EX+ and EX– terminals on the
connector to connect one external excitation voltage source to the
module. You can use the additional EX+ and EX– terminals on the
connector to wire multiple NI 9237 modules together in a daisy
chain.
Note When you insert or remove a new sensor from the
NI 9237, slight changes in the excitation voltages can
cause a mismatch between the internal half-bridge
completion resistors and the half-bridge sensors, which
results in a change in the measurement offsets.
National Instruments recommends performing bridge
calibrations of quarter- or half-bridge sensors after
connecting all sensors to the NI 9237 and after removing
or attaching any additional sensor. Visit
ni.com/info
and enter the info code rdw9237 for more information
about changes in voltage offsets in the NI 9237.