10
Modicon Communication Driver Manual
Introduction
The Operator Station can be used with any of the Modicon PLCs that have Modbus capability. You
may use the Modbus ASCII mode driver or the Modbus RTU mode driver to communicate Modbus to
Modicon PLCs. The driver takes responsibility for communications to this programmable controller,
generating the protocol necessary to request information from and send information to the PLC. The
PLCs simply respond to these requests and commands. No ladder logic is required in the PLC to
support the interface to the Operator Station. The information in this manual is for the Modbus ASCII
and Modbus RTU mode drivers only. Depending on the driver selected in the PLC Name and Port
Table, you must select either ASCII or RTU mode to communicate to an Operator Station.
Memory
The following memory types are supported by the Modbus ASCII and Modbus RTU (Micro 84, 184,
384, 484, 584, 884, and 984) mode drivers.
0XXX
Coils/discrete
outputs
0XXXX
0XXXXX
1XXX Discrete inputs (read only)
1XXXX
1XXXXX
3XXX Input registers (read only)
3XXXX
3XXXXX
4XXX
Holding/output registers
4XXXX
4XXXXX
Note:
For Modicon PLCs, “F”: must precede all holding registers to designate a floating point
number.
