Voltage Acquisition Discrepancy from proximity sensor using NI 9207 module

[jay8]

Hello experts,

I am having a proximity sensor which requires an external power supply to power up and outputs voltage signals in the range of 2V to 10V corresponding to the distance measured (2 to 55mm). I have attached the connection drawing to NI 9207.

When i connect the sensor i am able to display the output voltage using DAQmx. When i begin to increase the distance and the output voltage comes close to 10V, my voltage reading on the DAQmx gets hanged at 10.39V. Even after reducing the distance, the voltage output doesn't change. The output value gets stuck at 10.39V even after all connections are removed. I did check the sensor output using multimeter and i am able to get varied output on the sensor side but the NI 9207 voltage display is stuck at 10.39 V.

Understand NI 9207 has +/-10V rating, the sensor output voltage is 2 to 10V from manufacturer. If the sensor output exceeds the 10V value how will the NI 9207 respond ? What could be the issue that the Output reading is stuck at 10.39V ?

[GerdW · Accepted solution]

Hi jay,

your sensor should also be connected to GND of your power supply!

Connecting just the +24V line isn't sufficient to have it working…

[jay8]

HI GerdW,

Thanks for your reply. Apologies for making a mistake in wiring drawing in initial post. This is the actual wiring of the sensor.

I have connected the ground of power supply to COM of NI 9207 and then i have connected the GND of sensor to COM of NI 9207.

Thanks & Best Regards

Sanjay Menon

[GerdW]

Hi Sanjay,

I would connect the sensor directly to the power supply, but (if done right) that should not matter here.

- Which kind of measurement method did you use for your NI9207? Single channel (to GND) or differential (between two channels)?

- Can you attach your VI? (In case you are using LV2018 please downconvert your VI before attaching.)

- Can you attach a manual of your sensor or atleast provide the correct name/type?

[jay8]

Hi GerdW,

I had re-wired the setup and it worked. Looked like connecting the sensor to the GND of supply was the key. Thank you !