Constant Scan - Mitsubishi Electric MELSEC iQ-R-R00CPU User Manual

28.9

Constant Scan

The following describes the precautions for setting the constant scan in the redundant system.
Increase in scan time
In the standby system, when the CPU module is powered off, a hardware failure has occurred, or a tracking cable has a
failure, the scan time will increase in the control system.
When setting the constant scan, take one of the following measures.
• Set the setting time of the constant scan by adding the increase in the scan time when an error occurs. ( Page 926
Increase in the scan time due to tracking transfer)
• When a failure has occurred and a continuation error occurs due to the excess of constant scan time, clear the error. (
Page 133 Error Clear)
System switching in separate mode
When the systems are switched in separate mode, the scam time of the control system will increase by the increase of the
standby system scam time.
When the constant scan has been set, a continuation error may occur due to the excess of constant scan time because the
scan time of the control system increases.
When a continuation error occurs due to the excess of constant scan time after the system switching in separate mode, clear
the error.
For program executed in both systems
The constant scan function is invalid for the standby system in backup mode.
28 FUNCTIONS
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28.9 Constant Scan