DAQCard-6024E returns all zeros

[johnsackett]

I am using DAQCard-6024E on a 120MHz Pentium desktop running Windows 95 and LabVIEW Run-time 6.1. To duplicate the problem, I built an executable for the Acquire N Scans example and entered Channels 3:0, Number of Scans 1000, Scan rate 20000, and clicked Run Continuously. It works fine for an hour or so, but then the signal changes to identically zero (no noise). After this, the only way I have found to get it going again is to power down the computer or hot unplug/plug the DAQCard-6024E. Re-booting without turning off the power does not work. I have used the same DAQCard-6024E on another computer running Windows 98 and never seen this problem.

What is the cause of this problem and what can I do about it?

[Filipe A.]

Hello;

By my understanding, you are trying to do a continuous acquisition. To press the run continuously buttom is not a good way to accomplish that task. There is another example you can run instead, that will pretty much do that for you.

You can find the example at Find Examples->Hardware Input and Output->DAQ->Analog Input->General->Continuous Acquisition and Chart(buffered).vi.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments

[johnsackett]

No, this is just an example that you can easily duplicate that shows the problem. What I want to know is why does the DAQCard-6024E start giving no output after a while?

One of my actual programs is like an oscilloscope. It takes a sample, then stops sampling while it displays it, then takes another sample. This is somewhat like running Acquire N scans continuously. I only did that because the problem does not occur frequently, so you have to run it many times for the problem to show up. Acquire N scans does not have a repeat built in, but the Run continuously is an easy way to make it repeat.

[djetelina]

John,
I am having exactly the same problem at present w/ a 6071E card that we are using to collect high-speed machine information at a refinery. We are using a Azonix 2030 industrial PC running XP Pro. The 6071E runs in a continuous mode collecting data at 5,000 Hz over 25 channels fine anywhere from 12 hours to 50 hours. Then without warning we get the "all zeros" failure. Could you please let me know what you found to be the root cause of this phenomenon.
David Jetelina

[djetelina]

OK, I finally determined what the cause was and corrected it on my own. For those interested, the root cause was overheating, I took the 6071E over 55 deg C. Solution was to keep it under 55 C. Now all is well.
David J.