Chapter 13. Dedicated Cnet communication for GM6
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Chapter 13. Dedicated Cnet communication for GM6
13.1 Introduction
The GM6 CPU module provides some basic Cnet communication functions without Cnet module. Although all
functions of Cnet module are not supported, it will be very useful functions for users to perform simple Cnet
communication. If your needs are read/write variables (I,Q,M devices) and Monitoring, you don’t need to buy Cnet
module. It will save your money and slot for Cnet module.
The Cnet functions provided by CPU (A-type) module are as following;
n
Individual read instruction
n
Continuous read instruction
n
Individual write instruction
n
Continuous write instruction
n
Monitoring variables registration
n
Monitoring execution
n
1:1 communication only (dedicated protocol)
n
RS-232 communication only
Because the dedicated Cnet communication for GM6 does not support all functions of Cnet
module, there are some limitations as following comparison with using Cnet module.
1) At the pressing time, the RS-422 protocol is not supported. Only RS -232C protocol is supported. (RS422
protocol will be available with the next version of GM6 CPU.)
2) Only the 1:1 communication is available. The 1:N communication (multi-drop) which have Master & Slave
station will be available with the next version of GM6 CPU.
3) Because the GM6 CPUA module has only one serial port supports RS-232C, the general RS -232C cable
can not be used. Also the cable for Cnet module can not be used with GM6 CPUA module. See the chapter
13.3 of this manual for the detailed pin assign for GM6 CPUA module.
Note