Wheatstone Bridge Measurement

Hello, I have a question about a specific measurement setup.
We are trying to set up a measurement for the output voltage of a Wheatstone full bridge. We have connected a Keithley 2200-20-5 programmable power supply on points 1 and 3 of a Wheatstone full bridge (opposite of each other) and set that to output 100mV. We then connected a Keithley 2450 SourceMeter to points 2 and 4 of the full bridge and now want to measure the output voltage of the Bridge. However, we are having trouble correctly programming the SMU. Is source current (setting to 0nA) and measure Voltage the right function for this setup and do you activate the output? When doing so the SMU shows to limit the Voltage even tho the Limit is set slightly above the 100mV used as excitation Voltage, which seems strange to me. The SMU also randomly shows voltage values if the power supply is turned off and its own output is turned on (even for 0nA). We do not know if this measurement is correct or reliable. Does anyone have experience with such a measurement setup and how to realise it using the aforementioned instruments? Thanks a lot for the help!

Hello,
I would increase your limit quite a bit for measuring and see if that works for you.
To reference to your measurement reliability, you can check if the 2450 is within spec by sourcing directly to the SMU with the power supply to verify this voltage measurement.
If you are seeking to measure voltage, sourcing 0nA on lowest range will allow you to measure voltage. This will require you to turn the output ON.
As for the readings you are seeing when the power supply is off, this is normal as there can be many different environmental factors that could give just enough signal to be picked up by our SMU's.
From what I can tell your setup seems to be correct.
Let me know if this information helps!