Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 151

■ Available execution type
The online change (inactive SFC block) can be executed to a scan execution type program (cannot be executed to a standby
type program).
■ Availability depending on block status (active or inactive)
The online change (inactive SFC block) can be executed to a block that has been already inactive at the start of writing
(cannot be executed while a target block is active
*1 While SM321 (Start/stop SFC program) is off, the online change (inactive block) can be executed regardless of a target block status
immediately before SM321 turns off. Note that an SFC program changed online while SM321 is off always starts in initial start mode,
regardless of the following setting.
 SFC Program Start Mode Setting (Resume Start) in the CPU parameter ( Page 130 SFC program start mode setting)
 SM322 (SFC program start status)
■ Online change (inactive SFC block) when two or more blocks are changed
The online change (inactive SFC block) cannot be executed when two or more blocks are changed. When two or more blocks
are required to change, execute the function for each block change.
■ Changing/adding/deleting a block
The following table describes available operations (changing, adding, or deleting a block) in the online change (inactive SFC
block).
Operation Description
Changing a block • An existing SFC block program in the CPU module can be changed.
• An SFC information device set in a target SFC block can be changed.
Adding a block • An SFC block can be added to an SFC program in the CPU module.
• An SFC information device can be added to a target SFC block.
Deleting a block • A specified SFC block can be deleted from an SFC program in the CPU module.
• An SFC information device set in a target SFC block can be deleted.
• When a target block is not in an SFC program in the CPU module, deleting a block cannot be performed.
■ Area to be overwritten
The following table describes the area to be overwritten by execution of the online change (inactive SFC block).
Item Description
Area to be changed Changed steps or transitions in a target block are overwritten. (Steps or transitions which are not changed are not affected.)
SFC information device The following SFC information devices can be added, changed, or deleted.
• Block start/end bit
• Step transition bit
• Block pause/restart bit
• Block stop mode bit
• Number of active steps register
• Continuous transition bit
■ Changing the execution type of a program during the online change (inactive SFC block)
The execution type of a program being written by the online change (inactive SFC block) cannot be changed by using the
program control instructions (the POFF and PSCAN instructions). If the instructions are executed, they result in non-
processing.
■ Checking execution status
Execution status of the online change (inactive SFC block) can be checked in SM329 (Online change (inactive SFC block)
status flag) and SD329 (Online change (inactive SFC block) target block number). ( MELSEC iQ-R CPU Module User's
Manual (Application))
■ Reserved area for online change
Secure reserved area for online change by the amount to be added/changed through the online change (inactive SFC block).
When the amount of data added/changed through the function exceeds the reserved area for online change, the reserved
area setting can be revised as long as the program memory has enough free space.
For details on the reserved area for online change, refer to the following.
 MELSEC iQ-R CPU Module User's Manual (Application)
■ Online change (inactive SFC block) during the boot operation
When the online change (inactive SFC block) is executed while booting from an SD memory card, the corresponding files on
the booting SD memory card can also be changed.
*1
).
8 SFC PROGRAM
8.7 SFC Program Execution
8
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