NI NI-9237, Начало работы

Страница: 9 / 10

Bridge Calibration
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. NI 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. For more information about changes in voltage
offsets in the NI-9237, visit ni.com/info and enter the Info Code rdw9237.
Connecting a Quarter Bridge
You can connect a quarter bridge to the NI-9237 by adding a resistor externally to
create a half bridge.
Figure 4. Connecting a Quarter Bridge to the NI-9237
You also can use a quarter bridge with the NI-9237 with RJ-50 if you use the NI 9944
or NI 9945 Quarter Bridge Completion Accessory.
Connecting TEDS Sensors
You can connect TEDs sensors to the NI-9237.
Figure 5. Connecting TEDS Sensors to the NI-9237
Ensure that neither the TEDS data (T+) nor the TEDS return (T-) signal is tied in
common to any AI signals on the NI-9237. The NI-9237 connects all the T- signals
together internally. The NI-9237 with DSUB has only three T- pins. To connect four
TEDS sensors to the NI-9237 with DSUB, wire the TEDS return signals of two of the
sensors to one of the T- pins.
© National Instruments
9
NI-9237 Getting Started