Chapter 3: Modicon PLCs Using Modibus Plus
27
Introduction
An Operator Station, with an optional Modbus Plus interface board, can communicate with Modicon
controllers that have Modbus Plus compatibility. The Operator Station appears as a node on the
Modbus Plus network (similar to an SA85 network adapter). The interface board has responsibility for
establishing and maintaining communications across the network. No ladder logic is required to
support the interface.
Memory
The following memory types are supported by the Modbus Plus interface board:
XXXX
Coils/discrete
outputs
XXXX
Discrete
inputs
(read
only)
3XXXX
Input
Registers
(read
only)
4XXXX
Holding/output registers
900XX
Global
data
(read
only;
range
1-32)
G00XX
Global
data
(Operator
Station’s
node
range;
1-32)
Note:
G00XX requires the use of the GLBL prefix.
