NI 9219 won't real load cell anymore

[kyle.hall]

Hi All,

I’m stumped and need some help.  I have 2 identical test cells that have cDAQ-9172 each with 1 NI 9219, 1 NI 9215 and 2 NI 9401.  Each system has been in service with no issues for quite some time and the test cells are set up such that they can share cables, load cells and all other sensors required for testing.

Yesterday one system refused to red the load cell after about 10 tests.  Most of the time this is a cabling issue but after checking all of the cables all cables proved to be OK.

I then reset the chassis and did a self test on all of the modules and everything was OK. 

I then reset the computer, reset the chassis and did a self test on all of the modules and everything was OK. 

I then replaced the NI 9219 module with a spare, reset the chassis and did a self test on all of the modules and everything was OK. 

I then reinstalled the .vi, reset the computer, reset the chassis and did a self test on all of the modules and everything was OK. 

The 9219 is putting out an excitation of about 2.8 VDC which is what I would expect but the analog input is sitting at 0.85 volts.  I am not sure what this means and am hoping someone can give me a direction to go.

Thanks,

Kyle

[Che_T.]

Hello Kyle,

You've done the same troubleshooting procedure that I would have done. So, at this point, we can move forward.  Can you please clarify a couple of questions that I have?

1) Does this test normally run smoothly?  If not, how long does it last before failure?

2) What do you mean by the analog input being 0.85V?  Is it connected to a sensor, but the reading is off?  Or is it not connected to anything and giving that reading?

It is possible that there is a grounding issue.  Please refer to this KB for more information

http://zone.ni.com/devzone/cda/tut/p/id/5362