fargiolas / py-opc-ng Goto Github PK

I have a OPC-N3 connected to Raspberry PI via USB to SPI cabling. I have three of these setups and can successfully connect to the OPC and read data 50% of the time.

Upon reboot or at random sampling windows i receive the following error:

ERROR:opcng:Error while reading bytes from the device: Received unexpected response 0x3F for command: 0x3F 

Traceback (most recent call last): 

File "test_opc.py", line 10, in  

dev = opc.detect(spi) 

File "/usr/local/lib/python3.7/dist-packages/opcng/init.py", line 680, in detect 

info = o.info() 

File "/usr/local/lib/python3.7/dist-packages/opcng/init.py", line 381, in info 

buf = self._read_bytes(_OPC_CMD_READ_INFO_STRING, 60) 

File "/usr/local/lib/python3.7/dist-packages/opcng/init.py", line 302, in _read_bytes 

logger.error('Something failed while reading byte sequence, expected size: {}, received: {}'.format(sz, len(l))) 

NameError: name 'l' is not defined

Any suggestions as to what may be causing this issue?