CJ1W-PRM21 Operation Manual

6 Message Communications

6-1 Overview

Message communications enable messages to be sent between nodes on a PROFIBUS network when required by system conditions. It is possible for messages to be sent between a CPU and a PROFIBUS

Master or Slave Unit. You can use them to send/receive data; read time data, error logs, and other data; or control specific operation, e.g., clearing the error log.

There are three types of messages:

• Explicit

• PROFIBUS

• Other

The figure below depicts the command structure for the CJ1W-PRM21 PROFIBUS Master units

CPU Unit

Other message

PROFIBUS Master Unit

Other message function

SendCMd

Instruction

(0101 Hex)

(2103 Hex)

SendCmd

Instruction

(2809 Hex)

2809 PROFIBUS message

PROFIBUS message function

SendCmd

Instruction

(2801 Hex)

2801 Explicit message

Explicit message function

PROFIBUS network

PROFIBUS message

DP-V1 Explicit message

6-2 CJ-series PROFIBUS Master Unit Operation Manual for NJ-series CPU Unit (W509)