DT9816 All Channels Suddenly Change Reading

[AdamM2]

Running sw for capturing 6 channels simultaneously at 750ksps.   This worked flawlessly 2 years ago.  

Now I've installed it to a new W10 PC.  Same sw, which is a custom modification of the LV sw supplied.

The sw monitors all 6 channels looking for % change in DC voltages on any one of them.  Test runs should have no changes but randomly all channels "glitch".   See the plot below.    I haven't been able to catch the DC supplies that provide the signal glitching, so I'm starting to doubt this is really happening.

Furthermore, if you look at the plot, each channel jumps in value....but not to a random value, but to that of one of the other channels.  i.g. the white trace jumps to light green value, red to purple, blue to red, etc.   What would cause that? Its certainly not the DC supplies.

[JRys]

Hello,

If it previously worked and you haven't changed anything, it should still work. You could try using QuickDAQ to see if it too shows the glitches. You could also disconnect the channels and short them to ground to see if the glitches still happen. It could also be noise generated by nearby equipment. It is hard to say what it is.  

Best regards,
John

[AdamM2]

It looks to be the DAQ.  I tested all 6 channels with fixed voltage.  Also monitored the current to ensure it was the same.    

BUT after a random amount of time the voltage readings on each channel just swap with another channel.  The image here shows 6 channels with predefined and steady voltage, then a few minutes later the exact same voltages are present however their channels (as seen by the different colors) are switched around.  Its funny!

I don't think my code is causing this because, from above pic, the graph data is straight out of DtOLReadMultiple2D.vi, which is the raw data. 

Any ideas at all? firmware update?  Reinitialize every few minutes? Replace the DAQ?

[JRys]

There's no firmware update for the DT9816 series, and I'm unfamiliar with DtOLReadMultiple2D.vi. I cannot locate it in the ..\User.Lib\LV-Link3 folder. Instead, could you test with DtAinContinuous.vi? It is in the Examples folder. To enable six channels, enter 1,2,3,4,5,6 in the Channel control. Set the Sample Rate to 125000 and the Samples per Channel to 20000.

If it's the device, it can be repaired. If your need is immediate, the DT9816-S is a stock item. 

Best regards,
John

 

[AdamM2]

It is working fine on my older W7 PC.  Maybe theres sw version that is mismatched or something about W10 OS?

[JRys]

Hello,

I don't have a DT9816-S to test, so I ordered one, which will arrive sometime next week. In the meantime, did you get a chance to run the DtAinContinuous.vi on the Windows 10 PC? I'm curious if it, too, had the problem. 

Best regards,
John

[JRys]

Hello,

I've received my DT9816-S but would like help to duplicate your reported problem where the channels change position. I tested with the DtAinContinuous.vi with the six channels enabled and the sample rate set to 125k Hz. After collecting over 500 million scans, the channels did not change position.  The computer I'm using is an Intel i7 running Windows 10. 

Best regards,

John