John John - 17 days ago 7
Python Question

ValueError: "port" must be None or a string, not <class 'int'>

Good day everyone,

I am trying to issue commands to my usb connected lock controller. The code runs fine until this line:

Connected ports:
['COM6']
Please enter the port number that has port connected.
i.e. if COM3 is shown, enter 3 when ask to enter port number.
If the above shows [] than no connected port is found and errors will follow
Please enter the port number: 6


and the following error came up:

ValueError: "port" must be None or a string, not <class 'int'>


I get the following error:

Traceback (most recent call last):
File "[...]", line 44, in <module>
serial_connection() #executes the function defined above

File "[...]", line 29, in serial_connection
ser.port = COMPORT - 1 #counter for port name starts at 0

File "[...]", line 260, in port
raise ValueError('"port" must be None or a string, not {}'.format(type(port)))


Below is the code:

#this library is required as it helps establish the serial connection
#Using pyserial Library to establish connection
import serial #not being used because it was already called in portRead
from portRead import *

#Global Variables
ser = 0

#this will print out the port that can be used; ports that are connected. i.e. if COM3 is shown, enter 3 when ask to enter port number
#if shown [] then no usb is connected to a port and errors will follow
if __name__ == '__main__':
print ("Connected ports: ") #print means printing information on screen
print(serial_ports()) #function derived from portRead
print("Please enter the port number that has port connected. \n "
"i.e. if COM3 is shown, enter 3 when ask to enter port number. \n If the above shows [] than no connected port is found and errors will follow")

#defining the serial connection
def serial_connection():
while True: #the while loop is used to continuously ask you to issue a new command until you decide to quit the program
ser = serial.Serial()
ser.baudrate = 38400 #Suggested rate in Southco documentation, both locks and program MUST be at same rate
COMPORT = int(input("Please enter the port number: ")) #this refers to which port your usb is inserted into
ser.port = COMPORT - 1 #counter for port name starts at 0

print ('Port %d entered Stephan '%COMPORT)
#timeout in seconds
ser.timeout = 10
ser.open()
command = input("please type command - open1/close1, or open2/close2. \n"
"If already open and you try to open no action will be taken and vice-versa...: \n ")
#call the serial_connection() function
ser.write(("%s\r\n"%command).encode('ascii')) #Southco locks receives and sends commands in ASCII


serial_connection() #executes the function defined above


Any help would be appreciated as I am working around resolving this issue

Answer

you have to specify the port name in ser.port as a string, not just the number (as I guess it could be PRN, not only COMx).

fix suggestion:

COMPORT = int(input("Please enter the port number: ")) #this refers to which port your usb is inserted into
ser.port = "COM{}".format(COMPORT)

check the doc: https://pythonhosted.org/pyserial/shortintro.html#opening-serial-ports