Instruction Manual

275Publication 1753-UM001C-EN-P - March 2010 275
Chapter 22
Communicate with Modbus and Profibus
Devices
Introduction
Modbus RTU Slave
Protocol
Modbus is available only on GuardPLC 1600 or 1800 controllers. You
can connect a Modbus master to the controller’s COMM1 port. This
Modbus connection is two-way non-safety-related communication
between the controller (slave) and the master device. You cannot
program the controller by using this port.
The controller is a Modbus RTU slave device and responds only to
reads and writes from the master.
To use the Modbus function, signals that you wish to send out/receive
into the COMM1 port must be connected to placeholders in the
Modbus-protocol Connect Signals dialog box.
Topic Page
Modbus RTU Slave Protocol 275
Connect the Controller to a Modbus Device 276
Configure the Modbus Serial Port 276
Connect Signals 277
Profibus DP Slave Protocol 279
Connect the Controller to a Profibus DP Device 279
Configure the Profibus DP Serial Port 280
Connect Signals 280
Configure the Profibus Master 282