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GPIB bus slows down after accessing COM port

I have a program that accesses the GPIB port to setup an Agilent MXA spectrum analyzer, then I program a device using the COM port (via the Basic Serial Write and Read VI).  However, in the next sequence when I try to do a measurement on the MXA, the sequence goes very slowly.  

 

If I were to run the subVIs independently, i.e. run the GPIB MXA subVI, then run the COM port program, then run the GPIB MXA subVI again, the MXA sub VI runs quickly.  In my overall program, I've traced the problem to the potential slowing down of the GPIB bus after the COM port had been accessed.  Can you tell me if there is some bus/port reset that I need to do in order for the GPIB program to continue running as quickly as before in the overall program?

 

Now If I shut down LabView and restart and run the subVIs independently, the GPIB MXA subVI runs quickly each time, i.e I run the COM port program and then run the GPIB MXA program again, no issues.

 

Any insights will be greatly appreciated

Thanks,

hiNi.

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@hiNI wrote:

I have a program that accesses the GPIB port to setup an Agilent MXA spectrum analyzer, then I program a device using the COM port (via the Basic Serial Write and Read VI).  However, in the next sequence when I try to do a measurement on the MXA, the sequence goes very slowly.  

 

If I were to run the subVIs independently, i.e. run the GPIB MXA subVI, then run the COM port program, then run the GPIB MXA subVI again, the MXA sub VI runs quickly.  In my overall program, I've traced the problem to the potential slowing down of the GPIB bus after the COM port had been accessed.  Can you tell me if there is some bus/port reset that I need to do in order for the GPIB program to continue running as quickly as before in the overall program?

 

Now If I shut down LabView and restart and run the subVIs independently, the GPIB MXA subVI runs quickly each time, i.e I run the COM port program and then run the GPIB MXA program again, no issues.

 

Any insights will be greatly appreciated

Thanks,

hiNi.


Could you upload a gutted version of your main VI with your subVIs in place?  That would help us to better undersatand your problem and eliminate a lot of guesswork.  🙂

Bill
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My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
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Hello,

 

I found an error in the COM port subVI, where the port was continually being polled.  I removed the polling and the slow down issue went away.

 

Thanks,

hiNI.

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Excellent!  Mark your post as the solution so other people may benefit from your wisdom.  🙂

Bill
CLD
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
Humble author of the CLAD Nugget.
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