©
National Instruments Corporation
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2
Using the Module
This chapter describes how to connect Wheatstone bridge sensors to the NI PXIe-4330/4331
in quarter-, half-, and full-bridge configurations and for remote sensing. It also provides the
I/O connector signal pin assignments of the module.
Connecting Signals
This section includes a brief description of a general Wheatstone bridge and discusses how to
connect the signals of supported strain-gage configuration types. It also discusses connecting
leads for remote sensing and shunt calibration.
Refer to the
NI SC Express 4330/4331
Installation Guide and Terminal Block Specifications
for more signal connection
information.
Wheatstone Bridges
Many sensors including strain-gages, load cells, pressure sensors, and torque sensors are
based on the concept of a Wheatstone bridge. There are four elements or legs in a Wheatstone
bridge. In general, these elements can be resistive or reactive, but in the majority of bridge
based sensors the elements are resistive. Most Wheatstone bridge based sensors use all
four legs of the bridge as active sensing elements. However, common strain gage
configurations include one, two or four active sensing elements. Figure 2-1 shows a
resistive Wheatstone bridge circuit diagram.
Figure 2-1.
Basic Wheatstone Bridge Circuit Diagram
+
V
CH
R
1
R
2
R
4
R
3
V
EX
+
–
