Hardware reference guide

CPU Modules
35013379 02 October 2007 171
Modbus
Connector
Pinouts
All Quantum CPUs are equipped with a nine-pin RS-232C connector that support
Modicon’s proprietary Modbus communication protocol. The following is the Modbus
port pinout connections for nine-pin and 25-pin connections.
Modbus Port
Modem Support
Modbus Port 1 has full modem interfacing ability. Modbus Port 2 RTS/CTS
connections function properly for normal non-modem communications but do not
support modems.
Start Controller may be
either stopped or
running.
Programmer may
make changes and
start/stop the
controller
N Y From Stop:
Enables
Programmer
changes, starts
controller.
From Memory
Protect:
Enables
programmer
changes, starts
controller if
stopped.
Key Switch Description
Key switch
Position
Controller Status Memory
Protected
From
Programmer
Changes
Will Accept
Programmer
Stop or Start
Key switch
Transition
Note: Although the Modbus ports electrically support existing Modbus cables, it is
recommended that a Modbus programming cable (Part # 990NAA26320 or
990NAA26350) be used. This cable has been designed to fit under the door of a
Quantum CPU or NOM module.
This document provided by Barr-Thorp Electric Co., Inc. 800-473-9123 www.barr-thorp.com