So I run this code which is supposed to cycle between these setpoints for ten seconds each. It all works as expected, but the problem is that sometimes the instrument does not respond. I would like to add an if statement that resends the message if there is no response. The problem is that Minimalmodbus exits out the script when there is no response. Is there any way I can bypass that error so that I can add the if statement?
The error occurs at line b = board.custommsg(). If the error didn't end the script, I could add an if statement to resend if b is empty.
import time
import readboard
import struct
import crc16
import os
import threading
def timer():
current = time.time()
while (time.time() - current) < 10:
print('\r', round((time.time() - current), 2), end='')
pass
board = readboard.comport('COM5')
setpoint = [50, 125, 250, 375, 500]
a = 0
while a < 10:
for x in setpoint:
msg = bytearray(b'\x7F\x06\x00\x05')
max = 550
integer = int((x/max)*65535)
i = struct.pack('<H', integer)
msg.append(i[1])
msg.append(i[0])
crc = crc16.getfilecrc(msg)
msg = crc16.addcrc(msg, crc)
final = bytes(msg)
b = board.custommsg(final, 8) #<---- this is where it errors out
t1 = threading.Thread(target=timer, args=())
print(' Setpoint: ', round((struct.unpack('>H', bytearray(b)[4:6])[0])*(550/65535), 2), end='\r')
t1.start()
time.sleep(10)
t1.join()
