Operation Mode Of The Sil2 Process Cpu; Operation Modes Of The System; Safety Operation Mode; Checking The Safety Operation Mode - Mitsubishi Electric MELSEC iQ-R-R00CPU User Manual

35.4

Operation Mode of the SIL2 Process CPU

This mode determines the operation of the SIL2 Process CPU and is fixed to redundant mode
Project)
*1 Use this mode when a redundant system is built.
35.5

Operation Modes of the System

This mode determines the operation of the system and is fixed to backup mode.
Operation mode
Backup mode
35.6

Safety Operation Mode

There are two safety operation modes: TEST MODE and SAFETY MODE. Running normally as a safety system or changing
a safety program and safety parameters can be selected.
Safety operation mode
SAFETY MODE
TEST MODE
SAFETY MODE (wait-for-restart)
*1 The same restrictions apply to this mode as those for SAFETY MODE.

Checking the safety operation mode

The safety operation mode can be checked in the following ways.
• TEST LED of the SIL2 function module ( MELSEC iQ-R CPU Module User's Manual (Startup))
• "Safety Operation Mode Switch" window of the engineering tool ( GX Works3 Operating Manual)
• Module information list of the engineering tool ( GX Works3 Operating Manual)
• Safety special register of the SIL2 Process CPU (SA\SD205) ( Page 885 List of Safety Special Register Areas)
35 BASIC CONCEPT
566
35.4 Operation Mode of the SIL2 Process CPU
Description
When an error or failure has occurred in the control system, the standby system is switched to the control system to
continue the operation. Even if a system failure has occurred in the control system, the standby system continues the
operation because data is transferred from the control system to the standby system at every scan.
Description
Mode for operating the safety system controlled by the SIL2 Process CPU.
In this mode, safety programs and safety parameters of the SIL2 Process CPU cannot be changed. Only device data
values in safety programs can be changed.
Mode for performing maintenance (such as setting changes and tests) of the safety system controlled by the SIL2
Process CPU.
In this mode, safety programs and safety parameters of the SIL2 Process CPU can be changed. Device data can be
changed by performing a device test.
*1
The system switches to this mode during the period of time from immediately after safety operation mode is changed
from TEST MODE into SAFETY MODE until the CPU module is powered off or is reset. Even if safety operation mode
is switched to SAFETY MODE, safety operation mode remains in this mode until the CPU module is powered off and
on or is reset. Programs are not executed in this mode. An error occurs if the CPU module is in the RUN state.
*1
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