Can I use a module like the NI 9237 to provide the 10Vdc and 28mA signal excitation that my torque sensor need?
When using more than one channel on the NI 9237 and selecting an excitation voltage, you need to be aware that the module can provide up to 150 mW of excitation power. The NI 9237 automatically reduces internal excitation voltages as needed to stay below 150 mW total power, unless you supply an external excitation voltage at the module's 4-pin EX+ and EX- connector.All measurements taken by the NI 9237 ADC are ratiometric which means they are a ratio of the voltage output by the bridge and the excitation voltage. This mitigates the effect of small drifts in excitation voltage.
Refer to the related links for more information about when and how to use external excitation with an NI 9237.
The 150 mW limit allows you to power half and full bridges as follows:
For more information, see the Excitation Voltages section of the NI 9237 Datasheet.
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