Chapter 3 Replacement Procedure; Specifications - Mitsubishi Electric MELSEC iQ-R Series Manual

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REPLACEMENT PROCEDURE
This chapter describes the procedures of online module change.
3.1

Specifications

This section describes the specifications of the online module change function.
• Here are the application and features of each method of online module change.
Replacement method
Changing a module by controlling
special relays and special registers
*1
Changing a module directly
*1 The direct change is not available for redundant function modules as a method of the online module change.
• After the target module is replaced with a new module, the module-specific information is restored into the new module
from the module-specific backup parameter saved in the CPU module or remote head module. This makes it possible to
continue the same operation even after the replacement.
• Online module change of when the system is configured using a CPU module is permitted provided that there is no stop
error. Even though the operating status of the CPU module is changed from RUN to STOP/PAUSE during online module
change, the online module change is allowed to continue. However, when the CPU module is reset or a stop error occurs,
the online module change is not able to continue.
• Online module change of when the system is configured using a remote head module is permitted provided that there is no
moderate error or major error. Even though the operating status of the remote head module is changed from RUN to STOP
during online module change, the online module change is allowed to continue. However, when the remote head module is
reset or a moderate error or major error occurs, the online module change is not able to continue.
Operating status
RUN
STOP
PAUSE
Initial
Reset
With a stop error occurring (CPU module)
With a moderate error or major error occurring (Remote head module)
Application
Suitable to replace a module through
an external device (such as GOT)
Suitable to replace a module easily
without any special operations
Merit
Controls can be started and stopped
at the desired timing.
No special operations are required.
Thus, the target module can be
replaced easily.
Whether replacement is allowed or not







3 REPLACEMENT PROCEDURE
Demerit
An external device (such as GOT)
needs to be prepared.
• When the direct change is enabled,
the system cannot judge whether
the module has been accidentally
removed or an online module
change operation is in progress.
• Until the removal of the module is
detected, the scan time is longer
than the scan time taken when the
other method is used.
3.1 Specifications
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