Troubleshooting SCXI-1140: different results from MAX test panels in NI-DAQmx and Traditional Devices

[braymp]

Greetings,

I had posted a question previously concerning a system using a series of sixteen SCXI-1140 amplifiers, mounted in two SCXI-1001 chassis (8 amps each), each of which is connected to a PCI-6070E DAQ card. The signals from the 1140s are multiplexed to the DAQ. I think I have that problem worked out.

Another issue is now perplexing us, unrelated to the first. One of the 1140 amplifiers (named SC1Mod5 in MAX) seems to be acting oddly. When we input a test pulse train, and look at the output in the test panel under 'Ni-DAQmx Devices' in MAX, it shows a floating voltage for ai0:7. But when I examine the output in the test panel for the corresponding connected DAQ device in 'Traditional devices' and enter 'ob0! sc1! md5! 0:7' for the channel range, it shows the test pulses just fine.

Anyone know a reason for the discrepancy?
-Mark

[George M.]

Hi,

The first that I would try is to change slot locations of the module that is acting strangely, and see if the same behavior is duplicated. If it isn't, then place a module that is working appropriately in that slot to see it's behavior. If it is, then there is possibly an issue with the module.

Are you able to see the same behavior in LabVIEW when you use DAQmx. I am assuming it is only this module that shows this behavior.

Let me know what happens.

George

[braymp]

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@George M. wrote:
Hi,

The first that I would try is to change slot locations of the module that is acting strangely, and see if the same behavior is duplicated. If it isn't, then place a module that is working appropriately in that slot to see it's behavior. If it is, then there is possibly an issue with the module.

Are you able to see the same behavior in LabVIEW when you use DAQmx. I am assuming it is only this module that shows this behavior.

Let me know what happens.

George

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It definitely is the one module that is acting in this way. I performed the same test you suggested a while back. However, I wanted to confirm whether it's (1) in fact a defective module (which I actually think it is), or (2) the module is fine, but (a) there is some difference between using the test panels for Traditional Devices and NI-DAQmx that I'm unaware of (I'm new to LabVIEW) or (b) a 1140 setting (or some such) that makes no ultimate difference to the final output. I wanted to make sure it's (1) before facing the time delay in sending the 1140 back to NI and waiting for another one (fortunately, it's still under warranty).

I'm not familar with DAQmx so I can't answer your question directly. However, in response to a previous question, one respondent uploaded a VI (Cont Acq&Graph Voltage-Int Clk.vi) from the shipping examples which allows me the same functionality as the MAX test panel. My understanding is that it uses DAQmx, and it shows the same floating behavior for that particular 1140.
-Mark

[George M.]

Hi,

From your description and troubleshooting, I feel confident that you will need to RMA the board. I would go ahead and contact NI, and begin the RMA process. You will need the Part # and Serial # for the module to complete the RMA.

Have a Great Day!

George