Wiring NI-9237, NI-9949, and strain gauges

[id9]

Hi everyone,

I have two wired strain gauges that I want to connect to an NI-9237 through an NI-9949. I also have an NI-9945. Unfortunately, I haven’t been able to collect any data so far, and I think I may be wiring it incorrectly.

Can anyone help me with the wiring on this and how to connect them to each other?

[ZYOng]

Please share your current wiring diagram so that we can help reviewing it.

[id9]

I’m using 2-wire strain gauges connected through an NI-9949 into an NI-9237 module.
Currently, I have:

EX+ (Pin 6) and RS+ (Pin 4) tied together to one pad on the gauge.

AI+ (Pin 2) connected to the other pad.
I also tried adding a precision 350 Ω completion resistor between AI− (Pin 3) and EX− (Pin 7), and a jumper between RS− (Pin 5) and EX− (Pin 7).

In software (Python via NI-DAQmx and in NI-MAX), I’ve set the bridge type to Quarter-Bridge I, excitation to 2.5 V internal, and the gauge factor to 2.06.
However, the readings stay constant at around ±51,000 µε, which looks like a saturated / open-bridge signal.
Could you please help confirm whether the wiring above is correct for a Quarter-Bridge I configuration using a 2-wire gauge, and if not, what modifications are needed?