I use a T7 connected via USB. After shutting down and booting my MAC I had the following problem sometimes (but not every time):
Kipling does not find the device and calling LJM_OpenS throws the error LJME_ATTR_LOAD_COMM_FAILURE.
After disconnecting and reconnecting the USB connection, everything works fine.
I'm using firmware version 1.0229, because (as posted in another topic) its the latest version that does not result in settling issues (interference between my AIN-channels)...
Any ideas how to solve this?
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1. Please make sure you're running the latest software:
https://labjack.com/support/software/installers/ljm
2. Does this happen every time you reboot the computer?
3. Is the T7 connected via USB when you reboot?
4. When are your shutting down the computer? Please make sure there are no programs talking to the T7 when you shut down.
5. Does it still happen if you disconnect all other USB devices?
1. Please make sure you're running the latest software.
I did
2. Does this happen every time you reboot the computer?
As written in the original post: it does not.
3. Is the T7 connected via USB when you reboot?
Yes
4. When are your shutting down the computer? Please make sure there are no programs talking to the T7 when you shut down.
There are no other programms communicating with the T7...
5. Does it still happen if you disconnect all other USB devices?
The only other device connected is the keyboard. And I need the keyboard to run the script...
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Even if we do not find the underlying cause of the error, it would be nice to find some fix or work-around.
I have not been able to reproduce the issue with LJM 1.1700, firmware 1.0229, and macOS 10.13.4. With the T7 connected via to the USB 3.0 bus the whole time: I tried shutting down, waiting some seconds, pressed the power button, then either tried to open with Kipling or with the eReadName C example. I tried this a couple of times and I tried it with restart (instead of shutdown/boot) a couple of times. There was no USB hub between the T7 and the computer.
You could try capturing a debug log of the problem. To do so, enable the debug log via the ljm_startup_configs.json:
https://labjack.com/support/software/api/ljm/function-reference/debuggin...
Then, edit the eReadName.c C example to sleep (e.g. MillisecondSleep(1000);) immediately after LJM_Open is called and before ErrorCheck. (The debug log may otherwise not get a chance to write to file with such a short run time.) Then compile eReadName.c
Then reboot and run eReadName.
If the problem occurs, attach /usr/local/share/LabJack/LJM/ljm.log to a post in this thread.
Also, you could try using a T7 watchdog, which causes the T7 to reboot after some given amount of time it doesn't receive communication. Details are there:
https://labjack.com/support/datasheets/t-series/watchdog
The problem did not reoccure the last couple of times, after disconnecting the T7 before shutting down and reconnecting it again after starting MATLAB. So this is a good-enough-work-around for the time being. I additionally will implement a watchdog, just to be on the save side.
If the problem should reoccure, I'll let you know!