Precautions For Replacing Melsap-Ii With Melsap3; How To Start The Sfc Program; Block Information (Information Device For Sfc) - Mitsubishi Electric MELSEC-A0J2H Series Handbook

7
PROGRAMS REPLACEMENT

7.6 Precautions for Replacing MELSAP-II with MELSAP3

Although the basic operations of the MELSAP3 are same as MELSAP-II, some specifications differ.
This section explains items that require special cautions when replacing.

7.6.1 How to start the SFC program

The SFC program is started by using a special relay for SFC program start/stop.
The special relay (M9101) for SFC program start/stop of A0J2HCPU is replaced with the special relay
(SM321) for SFC program start/stop of the Basic Model QCPU during the conversion from A0J2HCPU
to QCPU.
Note that some specifications of the special relay for SFC program start/stop differ between A0J2HCPU
and Basic Model QCPU.
MELSAP-II(M9101)
User turns ON/OFF.

7.6.2 Block information (Information device for SFC)

The procedure to execute "Block START/STOP" and "Reading of the number of active steps and active
step numbers", which use the block information (information device for SFC), differ between the
MELSAP-II and MELSAP3.
How to execute
Block START/
STOP methods
Reading the
number of active
steps and active
step numbers
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Specifications
The SFC program starts as the system
automatically turns ON by default.
Specifications
MELSAP-II
[START]
Turn the block active bit ON to
execute forced start.
[STOP]
Turn the block clear bit ON to stop,
and turn it OFF to execute forced
termination.
The number of active steps and
active step numbers of the block
can be read.
MELSAP3(SM321)
MELSAP3
[START]
Turn the Block START/STOP bit
ON to forcibly start the
corresponding block.
[STOP]
Turn the Block START/STOP bit
OFF to forcibly terminate the
corresponding block.
Only the number of active steps of
the block can be read.
Precautions for replacement
To start or stop the SFC program
according to user conditions, turning
SM321 ON/OFF using the program is
required.
Precautions for replacement
[START]
As "Block START/STOP bit"
replaces "Block active bit" when
the SFC program of A0J2HCPU is
replaced with QCPU, the program
correction is not required.
[STOP]
For the "Block clear bit", add a
program that resets the "Block
START/STOP bit". Delete the
program that turns the block clear
bit ON/OFF.
Use "Active step batch readout
instructions (MOV, DMOV, BMOV)"
to read active step numbers.