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Two U6 Pro device communication issues

U6 multiple devices communication issues

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#1 [email protected]

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Posted 13 May 2014 - 11:34 AM

I have 2 fixtures with both LabVIEW programs on the same computer, fixture #1 uses program # 1 and fixture # 2 uses program #2. Both programs talk to their respective U6-Pros based on the local ID. They were working fine for about 6 months, until yesterday they started cross communicating. Program 1 communicates with its own U6 or sometimes with the other U6. Program 2 does not work and I get error 1010 indicating that the U6 # 2 is already open and hence my program cannot communicate with it. If I open the Labjack Control Panel at this point it shows me that U6 # 1 is already open (which should be the case) and U6 # 2 is not open. However my LabVIEW program can't talk to it as program #1 seems to be locking up the second U6. Sometimes Program 1 will control the 2nd fixture instead of its own i.e. fixture #1. Physically changing the USB connection on the PC seems to work sometimes.


Restarting the PC does not work.

Changing the local IDs does not work

changing USB ports as mentioned earlier does seem to work sometimes

Both U6 devices have the latest firmware.


Anyone else experiencing this issue (I doubt it). I am out of ideas at this point as to what could be happening. Please lt me know if more information is needed.



#2 LabJack Support

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Posted 13 May 2014 - 12:13 PM

With no other software running, use LJControlPanel to confirm that each U6 has the Local ID you expect it to have.


From our LabVIEW_LJUD archive, try the example "Multiple U6 Efunction Loop Example.vi".  Put the desired Local IDs for AddressA and AddressB and see if it always talks to the correct devices.


Try opening 2 different examples, put in different Local IDs for each, make sure you turn off FirstFound, and then run them at the same time to see if they always talk to the correct devices.  Try "U6 eAIN with Loop and Chart.vi" and "U6 Efunction Loop Example.vi".

#3 [email protected]

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Posted 14 May 2014 - 11:40 AM

I had the First Detect Set to true for both devices, turned them off and it is working well again, thanks!

Also tagged with one or more of these keywords: U6, multiple devices, communication issues

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