NI USB-9237 User Guide and Specifications
12
ni.com
Completion Accessories for more information about these accessories and how to purchase
them.
Wiring TEDS Channels
Ensure that neither the TEDS data (T+) nor the TEDS return (T–) is tied in
common to any AI signals on the NI USB-9237. Visit
ni.com/info
and
enter the info code
rdteds
for information about TEDS sensors.
NI USB-9237 Connection Options
Wiring resistance can create errors in bridge circuits. The NI USB-9237
provides two mechanisms to correct for these errors: remote sensing and
shunt calibration.
Remote Sensing
Remote sensing continuously and automatically corrects for errors in
excitation leads, and generally is most appropriate for full- and half-bridge
sensors.
Long wire and smaller gauge wire has greater resistance, which can result
in gain error. The voltage drop caused by resistance in the wires connecting
the excitation voltage to the bridge is a source of gain error.
The NI USB-9237 includes remote sensing to compensate for this error.
Remote sense wires are connected to the point where the excitation voltage
wires connect to the bridge circuit.
Figure 8 shows a diagram of how the NI USB-9237 uses remote sensing.
Figure 8.
Remote Sensor Error Compensation
EX +
EX –
RS +
RS –
AI –
AI +
R
bridge
R
bridge
R
bridge
R
bridge
R
lead
R
lead
