31.10.2022, 20:28
One one of my LM I have a Modbus RS485 issue. I can get out data 1 out of 2 times. One call goes OK and I get data, second call results in a CRC error. I tried this with a readtest under Modbus. When I get a CRC error, the communication LED on the Janitza unit flashes green (that is OK).
With a profile that works on my other LM everything goes right.
I want to read out a Janitza power meter UMG20CM (it has a communication led), this device has Modbus address 1, speed 9600
I tried the following things:
a/ reverse polarity (then always crc errors, red error led on Janitza meter for communications)
b/ connect GND of LM and Janitza: no difference
c/ checked if the fase and neutral of the LM and Janiza aren't switched
d/ tried to lower speed 38400 --> 9600
e/ tried parity al variants (now no, 1 stopbit)
f/ tried other cabling, twisted pair stranded cable
Any tips to try?
With a profile that works on my other LM everything goes right.
I want to read out a Janitza power meter UMG20CM (it has a communication led), this device has Modbus address 1, speed 9600
I tried the following things:
a/ reverse polarity (then always crc errors, red error led on Janitza meter for communications)
b/ connect GND of LM and Janitza: no difference
c/ checked if the fase and neutral of the LM and Janiza aren't switched
d/ tried to lower speed 38400 --> 9600
e/ tried parity al variants (now no, 1 stopbit)
f/ tried other cabling, twisted pair stranded cable
Any tips to try?