Analog Output Issues (NI-9264 module)

[chuggins1434]

Hello all,

For full disclosure, I am working with support, but have been doing so for over 3 weeks now with no resolution as of yet.  So I thought I'd throw this out to the interwebs and see what sticks...

Situation:  Stand alone computer with an EXE that had been running fine for months.  Zero changes to the NI software or hardware.  Windows runs some updates and the next morning when we restart we have an issue...

Hardware: cDAQ-9174 (USB 4slot Chassis)

Issue:  Send a signal to the NI-9264 to output a voltage signal... dead on the money at any point below a certain threshold... in this case ~3vdc... unit should be able to put out 0-10vdc.  ..any signal to try and drive it above the threshold only results in that top voltage as an output.

Thought it might be a corrupted exe... so I shut it down and fire up MAX, when I attempt to drive it from a MAX test panel, I get the same results.

Maybe the module is wonky, so I swap it for another module, retest with MAX test panel, same results...

Maybe the chassis is bad?  Pull both modules to my development chassis (cDAQ-9185) and drive it from my development laptop (which has just ran the same windows updates)... retest in MAX, same results...

Generate tasks, one to generate a signal and one to measure... makes a perfect sine wave between -4/4 (max/min) and signal output range above/below that the wave has a flat top and bottom...

Pull a third chassis (cDAQ-9184) and tested with both modules, same results...

Install LabVIEW 2021, update to all the latest drivers in NIPM... have uninstalled and reinstalled more than once.  

Measured with an Oscope and installed a NI-9205 (AI module)... have ran through several grounding exercises with support, but I know that's not the issue as I've chased plenty of grounding gremlins in the last 25 years and know how to avoid those... along with the fact that the system was working fine one day and not the next. 

I need a more powerful kung-fu.  

Anyone have any suggestions or thoughts?

Thank you,

Chad

[AnalogKid2DigitalMan]

Was/is the module connected to an external device when you had the problems? If so try disconnecting it, if the problem goes away then perhaps the input impedance of the external device has changed due to a failure.

EDIT- Did you try a different power supply module for the chassis?

-AK2DM

[chuggins1434]

AK2DM, 

Thank you for the response...

When the issue first started I unhooked the hardware that the signal was going to and connected directly to a Fluke DMM.  This is how I narrowed down that it was not an issue with my hardware downstream.  

NI support had me try a different power supply to the chassis... it comes with a 12vdc supply (NI PN - 190415B-01), I switched to a 24vdc supply (2.5A)... no change.

Currently I'm testing in a cDAQ-9184 with the NI-9264 generating signals and a NI-9205 measuring with tasks in MAX... as a further confirmation, I have a Oscope to see sine waves and a FLUKE 179 to measure a DC signal... they're all lining up.

Thoughts?

Thank you,

C

[AnalogKid2DigitalMan]

I am out of ideas, can you roll back the last round of Windows updates (or at least look at what specific updates were applied and the KB details for clues)? I have had updates take out the NI Device Loader Service and re-enumerate DAQ device ID names, but nothing like what you are experiencing.

-AK2DM

[chuggins1434]

AK2DM,

Thankyou for the response.

Our corporate IT over minds are not really in favor of "going backwards" on the updates front... something about security and what not...  So that's not really an option, but I may press harder if this goes on much longer.

I'll have to look and see if I can figure out what updates were ran and when...  

Thank you for the ideas!

C

[daniel_fischer]

I have exactly the same issue; NI9264 AO module is supposed to be able to output any voltage between -10V up to +10V.  It used to work..... Now it is clipping at around 3V, but not always.... depends on what mood it is in; yesterday it was determined not to go above 3V, today it is 4V.  Ni cDAQ-9174 chassis.  Have tried on 2 computers, same issue.  Stopped my application and run NI Max; looking with a scope, and the sine is perfect for values below the upper clip.  So, no, it is not a grounding issue since everything below that value is rock solid.  I can see the clipping takes place at some value (e.g. 4V), voltage drops a bit, then it is flat, then the sine goes down, back up, and it clips.... but not quite the same at the same level.  

Here, screen shot, pleasantly surprised I can paste it....

[daniel_fischer]

One more comment....  The signal is not driving anything (except for the 1M input impedance oscilloscope.... so that does not count); it is not loaded

[santo_13]

My theory is that the Over-voltage protection circuit is activating prematurely at the clipping point and Short-circuit protection is also kicking in, the reason why that might happen can be understood only with access to the actual circuit. If you're curious, you can take apart the module, and see if any of the protection circuit parts are damaged and from what is damaged, one can hypothesize what might be the root cause of damage.

[chuggins1434]

All,

Okay, as a follow up... since this thread was posted on...  I ended up sending the two malfunctioning in for "repairs"... they covered one under warranty (even though it was out of the warranty period) and I paid for the other (that still pisses me off btw) to get them repaired... I never got a straight answer on what the issue was or what was done to fix it, but they're working today.  

Thanks,

C