Appendix 6 Use In A Redundant System; Restrictions - Mitsubishi Electric MELSEC iQ-R Series User Manual

Appendix 6
This section explains restrictions, considerations, and other information when using a C intelligent function module in a
redundant system.
Setting a different IP address for each C intelligent function module in system A and system B enables each module to enter
the same network.

Restrictions

The following shows the restricted specifications and functions when using a redundant system.
Applicable modules
When using a function supporting a redundant system, use the following modules:
• Process CPU
• Redundant function module
• RD55UP06-V with firmware version '12' or later, or RD55UP12-V with firmware version '05' or later
When using a redundant system, check the version of a process CPU and engineering tool. (MELSEC iQ-R Process CPU
Module User's Manual)
Mountable base units
A C intelligent function module must be mounted on the main base unit in a redundant system. It cannot be mounted on an
extension base unit or a redundant extension base unit.
System switching
A C intelligent function module does not support system switching in a redundant system. Therefore, a user program running
on a C intelligent function module keeps running even after system switching. In addition, requests from a CPU module and
the internal state of a C intelligent function module are not applied when system switching occurs.
To create a user program that operates according to the system, check the following in advance:
• Switch the processing of the user program in the control system or standby system according to the status of the special
relays (SM) and special registers (SD) in a process CPU (redundant mode).
• When system switching occurs, clear the data related to a C intelligent function module used in the sequence program and
user program, and perform all the processing again.
• When using a C intelligent function module in a redundant system, some functions are restricted.
For the restricted functions, refer to the following:
Page 109 Functions
System switching request to a CPU module in the control system
When an error occurs in a C intelligent function module, a system switching request is not sent to a process CPU (redundant
mode) in the control system. Perform system switching with a sequence program.
Ex.
The following shows an example of a procedure for system switching with a sequence program.
1.
With a sequence program, monitor the status of a C intelligent function module.
An error is detected when the C intelligent function module is in any of the following cases:
• 'Module READY' (X0) turns from ON to OFF (fall).
• An input signal (X10 to X1F) turns ON (an error is detected in a user program).
2.
If an error is detected with the sequence program, execute the system switching instruction.
For the instruction to perform system switching, refer to the following:
MELSEC iQ-R Programming Manual (CPU Module Instructions, Standard Functions/Function Blocks)
APPX
108

Appendix 6 Use in a Redundant System

Use in a Redundant System