Cross Automation - Application Notes - Modem Setup for Omron PLC

C R O S S A U T O M A T I O N . . . . A P P L I C A T I O N N O T E S

Project:
US Robotics External Modem Setup for
Communication with Omron C-Series PLC

Set your dip switches to the following for a US Robotics Modem .V90
1,2,3,4,8 =>On
5,6,7=>OFF

1. Modem ignores DTR(override)
2. Numeric Result codes
3. Enable Result code display
4. Command Mode Local Echo Suppression (Suppress echo)
5. Modem answers on First Ring
6. Carrier Detect always ON
7. Load Y0-Y4 on Power up from NVRAM
8. AT Command Set (smart mode)

NVRAM Settings (When using HyperTerminal “AT” must precede each setting i.e. AT&A1)
&A1 ARQ result code enabled
&B1 Fixed Serial Port rate
&H1 Hardware Flow Control Clear to Send (CTS)
&I0   Software flow control disabled
&K0 Data Compression Disabled
&M4 Normal/ARQ
&N6   Connection set to 9600 baud
&P0   U.S./Canada ratio
&R1   Modem ignores RTS
&S0   DSR override
&T5    Prohibit Remote digital loopback

Note: Don’t forget to save the changes to NVRAM. This command is AT&W0. This must be done because when DIP switch 7 is OFF the modem loads this custom set up from NVRAM.

Cable Pin Out
25Pin Male D-sub 9Pin Male D-sub
2---------------------------------2
3---------------------------------3
4---------------------------------5
5---------------------------------4
7---------------------------------9-7
6-20

Note: Check the PLC port setup. If using a CS1 and the port is set for NT Link, the modem will not answer. The modem will attempt to Auto Connect but will fail.