Access To Modules On The Extension Base Unit - Mitsubishi Electric MELSEC iQ-R Series User Manual

Access to modules on the extension base unit

This section describes precautions for accessing modules on the extension base unit.
• When an instruction to access the buffer memory of a module on the extension base unit from the standby system is
executed by SM1762 (operation setting for access from the standby system to the extension base unit), whether the
operation of the instruction is handled as a stop error or as non-processing can be selected.
• Do not set the interrupt condition for modules on the extension base unit. If the interrupt condition is set, a stop error is
detected at startup time.
• The monitoring/test function cannot be executed from the standby system by specifying a device to access the module on
the extension base unit. If executed, the following actions will be taken.
Function
Device/buffer memory batch monitor
Circuit monitor/watch
Device test
Intelligent function module monitor
• Module extension parameters cannot be written from the standby system to a module on the extension base unit by
programmable controller writing.
• Set a program execution time of the standby system to be within 200ms. When the program execution time exceeds
200ms, the standby system detects a continuation error. If operation is performed while the program execution time
exceeds 200ms, a major error of the CPU module of the control system causes system switching, and because a stop error
occurs in the CPU module of the new control system, control may not be continued.
• Configuration of the tracking setting for the following data is recommended, because the standby system does not refresh
modules on the extension base unit. If the tracking setting is not configured, the program is executed with the value before
refresh in the first scan of the CPU module of the new control system after system switching.
• Devices where refresh settings were made for the intelligent function module on the extension base unit
• Devices where refresh settings were made for the CC-Link module on the extension base unit
• If the control system is powered off or reset while the systems cannot be switched due to a tracking communication failure,
an error may occur in a module on an extension base unit. In this case, restart the CPU module of both systems.
11 BASIC CONCEPT OF REDUNDANT SYSTEM
178
11.8 Access in a Redundant System with Redundant Extension Base Unit
Device Operation
Un\G The engineering tool displays an error message. Execute the monitor function again from
the control system, not from the standby system.
DX The engineering tool monitor displays the X value for the own system.
Un\G The fixed value FFFFH(-1) is displayed.
DX The engineering tool monitor displays the X value for the own system.
Un\G The engineering tool displays an error message.
DY When DY is tested from the engineering tool, the test is performed for Y of the own
system.
Un\G The engineering tool displays an error message. Execute the monitor function again from
the control system, not from the standby system.
X/Y