U3 Interrupting a stream | LabJack

U3 Interrupting a stream

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Bee Research Pty Ltd
steven1's picture
U3 Interrupting a stream

Hi Guys, I have another rookie question. I'm writing some code in Python to stream 4 analogue inputs and control two analogue outputs. The outputs only change occasionally, but when they interrupt I get this error on the console:

LabJackPython.NullHandleException: Couldn't open device. Device access or claim error. Please check that the device is not already open in another or the current process.

What would be the best way to handle this problem?




LabJack Support
labjack support's picture
The exception you are seeing

The exception you are seeing should only be thrown when calling openLabJack. Only one process can claim the device connection at a time, so please ensure you only call openLabJack once and ensure no other processes that can claim the U3 connection are open while starting your script.