LabVIEW
Continuous analog output from NI9263 stops apparently at random
@hairykrishna wrote:
I'm trying to drive two rastering coils from a NI9263 module - this outputs two sine waves at a reference voltage that are fed into some amps. It's a very simple program - two sine waves 90 degrees out of phase.
The little vi I've written works perfectly for seemingly random amounts of time, sometimes hours, before the output stops. I'm using the analog out in 'continuous' mode.
The program doesn't seem to hang but just stops outputting. I'm fairly new at this so I'm sure it's a relatively simple issue!
Hey hairykrishna,
I've looked at your VI and everything you've done seems valid, although just to be sure I've modified it for error handling capabilities so that if an error occurs during operation the while loop will automatically halt execution and an error dialogue will be displayed. I've done this by taking the error cluster in the program and using the Unbundle by Name function in order to access the Status indicator, which will turn true whenever an error occurs; by wiring this to a Conditional OR boolean function which controls the operation of the while loop. This way, the while loop will automatically stop whenever you press the Stop button or an error occurs. I tested this VI on my own DAQ device so you'll need to quickly reassign the terminals to suit the output for your NI 9263.
From the issues you have described, it appears to me that you may just be experiencing a hardware based error due to a bad connection; this would explain why the VI only operates for random amounts of time. Do you move the NI 9263's terminal wiring around during it's operation? I recommend that you take some time to ensure solid connections are made to the device so we can be absolutely sure of the system integrity during operation.
I've taken a look at the DAQ Assistant that you have configured and have also noticed that you've set the DAQ's output to match an RSE (Single-Ended Ground Reference) connection. If this type of connection is wrongly implemented then Ground Loop can be introduced into your circuit; this causes problems in your signal. I want to make sure that your system matches the criteria explained in this article about proper source grounding in order to ensure that ground loop isn't affecting the outputs of your Operational Amplifier differential terminals. If you scroll to the bottom of the article there's examples on how to implement Differential and Single-Ended Nonreferenced (NRSE) circuits for floating and grounded signal sources; don't leave home without it!
After you've ensured that your circuit matches all of this criteria, your system should work because this problem you're having seems purely hardware based considering the program still functions even after the output has appeared to stop.
Please tell me how you get on!
