Chapter 26 Basic Concept; System - Mitsubishi Electric MELSEC iQ-R-R00CPU User Manual

26
BASIC CONCEPT
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
Process CPUs 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, and match the firmware versions of the Process
CPU and redundant function module. Use the engineering tool with the software version corresponding to the
firmware version of the Process CPU.
( Page 1008 Added and Enhanced Functions)
26.1

System

System A and system B
In a redundant system, one system is specified as a system A and the other is specified as a system B to distinguish between
two systems connected with tracking cables. Set the system A or B with the engineering tool. ( Page 431 System A/B
Settings)
When one system is set to system A, the other system is automatically set to system B, and vice versa.
Control system and standby system
In a redundant system, the CPU module in one system executes programs to perform controls. The other system is in the
standby state and does not perform controls. The system that performs controls is called a control system and the system in
the standby state is called a standby system.
A control system or standby system is determined when both the systems are started and ready for tracking communications.
( Page 410 Determination of Control System/Standby System)
26 BASIC CONCEPT
406
26.1 System
(1) (2)
(3)
(3)
(1) Process CPU (redundant mode)
(2) Redundant function module
(3) Tracking cable