Chapter 11 Basic Concept Of Redundant System; Concept Of "Systems" In A Redundant System - Mitsubishi Electric MELSEC iQ-R Series User Manual

11
BASIC CONCEPT OF REDUNDANT SYSTEM
This system consists of two basic systems that have a CPU module, a power supply module, a network module, or other
modules for each of them. Even if an error occurs in one system, control is continued with the other system.
A redundant configuration of the systems of main base units is available when redundant function modules are used and the
CPU modules are operated in the redundant mode. To build a redundant system, build the same system with modules on two
main base units, and connect the redundant function modules of each system by using tracking cables. Connect the
redundant function modules with two tracking cables to configure a redundant system of tracking cables.
(1) (2)
In a redundant system, match the both system configurations. When using functions added by the upgrade,
use a CPU module with a firmware version that supports the functions for both systems. ( Page 747
Added and Enhanced Functions)
11.1

Concept of "Systems" in a Redundant System

System A and system B
A redundant system consists of two identical systems. One system is called "system A" and the other is called "system B" to
distinguish between two systems connected with tracking cables. The system A or B is set using the engineering tool. (
Page 65 Setting the System (System A or System B))
When one system is set as "system A", the other system is automatically set as "system B", and vice versa.
Control system and standby system
In a redundant system, the CPU module of one system executes programs and controls the entire redundant system. The
other system will be in the standby state and does not perform control. The system that controls the entire redundant system
is called "control system" and the system in the standby state is called "standby system".
The control or standby system is determined when both systems are started up and tracking communications between the
two systems are established. ( Page 161 System Determination)
(1) (2)
(3)
(3)
(1) Process CPU (redundant mode)
(2) Redundant function module
(3) Tracking cable
11 BASIC CONCEPT OF REDUNDANT SYSTEM
11.1 Concept of "Systems" in a Redundant System
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