I’am preparing two scripts: one with class to communicate with DC Power Supply, and second to manage the communication.

dcom.py:

import socket

class supply:

    def __init__(self, IP, PORT, BUFFER_SIZE, TIMEOUT_SECONDS):
        self.IP = IP
        self.PORT = PORT
        self.BUFFER_SIZE = BUFFER_SIZE
        self.TIMEOUT_SECONDS = TIMEOUT_SECONDS
        self.connection = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    def opensocket(self):
        supply.connection.connect((supply.IP, supply.PORT))
        supply.connection.settimeout(supply.TIMEOUT_SECONDS)

    def sendAndReceiveCommand(self, msg):
        msg = msg + 'n'
        supply.connection.sendall(msg.encode('UTF-8'))
        return supply.connection.recv(supply.BUFFER_SIZE).decode('UTF-8').rstrip()
    
    def sendCommand(self, msg):
        msg =  msg + 'n'
        supply.connection.sendall(msg.encode('UTF-8'))

    def initialize(self):
        return supply.sendAndReceiveCommand('*IDN?')

    def readVoltage(self):
        return supply.sendAndReceiveCommand('SOUR:VOLT?')

    def readCurrent(self):
        return supply.sendAndReceiveCommand('SOUR:CUR?')

main_comm.py:

import dcom

SUPPLY_IP = '10.41.32.2'
SUPPLY_PORT = 8462
BUFFER_SIZE = 128
TIMEOUT_SECONDS = 10

supply = dcom.supply(SUPPLY_IP, SUPPLY_PORT, BUFFER_SIZE, TIMEOUT_SECONDS)

print(supply.connection)
supply.opensocket()

When I run the main_comm.py the result is:

<socket.socket fd=400, family=2, type=1, proto=0>
Traceback (most recent call last):
File “C:UsersRyszardDocumentsWroblewskiWDC_supply_commmain_comm.py”, line 11, in <module>
supply.opensocket()
File “C:UsersRyszardDocumentsWroblewskiWDC_supply_commdcom.py”, line 15, in opensocket
supply.connection.connect((supply.IP, supply.PORT))
^^^^^^^^^^^^^^^^^
AttributeError: type object ‘supply’ has no attribute ‘connection’

As you can see, first I can print the object attribute “connection” value, what I suppose means that this attribute exists. However, later I get an error that this object has no such attribute.
Do you have any idea how to fix it?