How Do I Connect To A C-Series, Peripheral Port Using A Modem? - CX-Programmer

Modified on Sun, 11 May, 2025 at 10:09 PM

Westermo industrial modems are recommended for use with Omron PLCs. This combination has been extensively used and tested. Set the Westermo DIP switches to 9600 baud, 8,E,1 protocol. Refer to Westermo installation manual for other DIP switch setting details.
Standard settings as below:

SW1 All off
SW2 All off
SW3 1 (2-wire) and 7 (DCD follows state of line carrier) On
SW4 2,3 (9600), and 7 (8,E) On
SW5 4 (9600 line modulation) On
All other DIP switches set to off.

The modem to Peripheral port cable (eg CQM1 CIF02) connection details must be as detailed below:

Modem 25 pin male PLC 9 pin male

Pin 1 shield Pin 1 shield
Pin 2 to Pin 2
Pin 3 to Pin 3
Pin 7 to Pin 5
Pin 4 short to Pin 6
Pin 6 short to Pin 20
Pin 4 short to Pin 9
Pin 7 short to Pin 8

Pins 8-19 & 21-25 not used. Pin 6 not used.

Set the Change PLC, Toolbus Network Type, Settings, Driver tab to 9600 baud, 8, E, 1 protocol.
Set the Modem tab to Standard Modem, 9600 baud, 8, E, 1 protocol. Select No Flow Control and set the "Connect To" options ie. Country code, Area code and Telephone Number. These "Connect To" settings are mandatory.

The Modem settings can be set to default in the OS "Control Panel", "Modem" section.

DIP switches should be set on the PLC where appropriate.
eg For CQM1H
Pin 5 Off - Peripheral Port set to settings in PC Setup (DM6650, DM6651.
Pin 7 On - Device other than Procon connected to peripheral port.

Use CX-Programmer to set the PLC Settings peripheral port to "Custom", 9600, 1, 8, E, 1 Protocol, and perform a download.