Hi,
I played around with this a lot to try to make PCBs, gave up because of the light scatter gave very poor tracks.
In doing so, I encounter all sorts of problems, including this one.
Try unplugging the USB, wait a few seconds and reconnect. The “backend device” is the USB interface.
I hope you are doing this in Linux, I didn’t even try under Windows since libusb will cause problems there.
Any error, crash or other unexpected result, re-plug the USB, it never cleanly sorts itself out otherwise. I wasted a lot of time before I realised this!
-Stuart
I am using windows and now i tried to use a virtual machine with ubuntu 17.10 . I installed dependencies (pip install -r requirements.txt ) and then i used these codes through python :
from OpenFL import Printer, FLP
p=Printer.Printer()
well i used sudo commands prior to opening python and its ok now. I am connected to the printer but i cant read FLP files from it. The only command that works on the printer is : p.initialize() that reset the printer
I realised that i am able to call every function that is located in the Printer.py ( like p.initialize() ) but i cant call functions from the FLP.py . I tried to use p.read_block_flp() and i got this error :