When Should I Provide an External Voltage to NI 9237 Module?

Updated Oct 15, 2018

Reported In


  • NI-9237

Issue Details

I am using a load sensor with NI 9237 module, when do I have to connect an external excitation supply?


Although the sensor industry does not recognize a single standard excitation voltage level, excitation voltage levels of between 2.5 V and 10 V are common. You can program the NI 9237 to supply 2.5 V, 3.3 V, 5 V, or 10 V of excitation voltage, and the module can provide up to 150 mW of excitation power. Unless you supply external excitation voltage, National Instruments recommends that you set the excitation voltage to a value that keeps the total power below 150 mW. The NI 9237 automatically reduces internal excitation voltages as needed to stay below 150 mW. Refer to the NI 9237 Datasheet to learn more about the power utilization in a bridge circuit.

If you need an excitation voltage greater than 150 mW, use the four-position external excitation voltage connector to connect an external excitation source to the NI 9237. Refer to How Do I Use External Excitation with the NI 9237 Module? to understand more about using the external excitation feature.