TypeError: ord() expected a character, but string of length 0 found

[MohitM-CIS]

#import the pyserial module
import serial
import socket
import ncd_industrial_relay as ncd
#set up your serial port with the desire COM port and baudrate.
serial_port = serial.Serial(port='COM11', baudrate=115200, bytesize=serial.EIGHTBITS, stopbits=serial.STOPBITS_ONE, timeout=.5)
#instantiate the board object and pass it the serial port
board1 = ncd.Relay_Controller(serial_port)
board1.turn_on_relay_by_index(1)
board1.get_relay_status_by_index(1)
#board1.turn_off_relay_by_index(1)

[RiebenRetus]

Could you figure out how to fix it? I have the same problem... And could need some help on how to get rid of it.

[telliottosceola]

Are you running this sample with python or python3? I believe this example requires python3.

[RiebenRetus]

I use python 3.10 in a venv on windows. I know it is not offically supported but I don't have another system. :-/

EDIT: if someone stumbles across the same error. You also get it if you have the wrong baudrate for your serial_port device so that the handshake does not work properly. maybe it helps someone.

[telliottosceola]

I did not write this example. However to test I downloaded the repo. I moved the Serial-Port-Relay-Example file up one directory so it was in the same directory as ncd_industrial_relay.pyc. I connected my relay controller to the computer via serial and determined the serial port. Then I edited the Serial-Port-Relay-Example on line 7 to specify the serial port of my relay controller(was COM 27). Then I renamed Serial-Port-Relay-Example to add .py to the end. Then executed with Python2.7 rather than Python3. It ran as it should. So I guess this example was developed for python2.7, not python3

[spukhafte-sys]

So I guess this example was developed for python2.7, not python3

The print statements in Serial-Port-Relay-Example don't have round brackets, which means it's Python 2. Has anyone got ncd_industrial_relay.py working under Python 3?

[RSyndergaard]

The print statements in Serial-Port-Relay-Example don't have round brackets, which means it's Python 2. Has anyone got ncd_industrial_relay.py working under Python 3?

I have ncd_industrial_relay.py implemented in Python 3. Same issue as op, which brought me to this post. Some cursory debugging showed me that the issue (traceback shows this occurring during check_handshake method) can be mitigated with wait statements between commands. Waiting 0.5s still leads to errors in less than 100 commands. Waiting 1s between commands, I successfully sent 250 commands without issue.

My application doesn't switch the relays often enough to root cause further than that, but I suspect the issue is related to the buffer and could even be on the windows side.