Mitsubishi MELSEC-A series, Programming Manual

Page: 189 / 508

6. BASIC INSTRUCTIONS
6
−
77
MELSEC-A
Counting of Counter Used with CHG Instruction
(1) When the A3 is used, execution contents of the counter change with status of
M9050 when other input conditions are same.
Status of M9050
OFF ON
Ladder example
The following program is written at step 0 of the main and subsequence programs.
Timing chart
OFF C0 count value remains unchanged. C0 cont value remains unchanged.
ON
C0 count value is incremented by 1 after END (FEND,
CHG) is executed during the first scan of the program
selected by the CHG instruction.
C0 count value is incremented by 1 after END (FEND,
CHG) is executed during the first scan of the program
selected by the CHG instruction executed after X0 is
switched on.
Operation
depending on
X0 ON/OFF
status
OFF
↓
ON
C0 count value is incremented by 1 after END (FEND,
CHG) is executed. C0 count value is incremented by 1 after END (FEND,
CHG) is executed.
(2) When the A3N, A73 and A3V are used, execution contents are always same.
Ladder example
The following program is written at step 0 of the main and subsequence programs.
Timing chart
OFF C0 count value remains unchanged.
ON
C0 count value is incremented by 1 after END (FEND, CHG) is executed during the first scan of the program
selected by the CHG instruction executed after X0 is switched on. Operation
depending on
X0 ON/OFF
status
OFF
↓
ON
C0 count value is incremented by 1 after END (FEND, CHG) is executed.
(
)
X000
K10
C0
1 scan
Main sequence
program run
CHG instruction execution
Subsequence
program run
X0 OFF
ON
C0 coil OFF
ON
C0 count value 1 2 0 3 4
CHG instruction execution
1 scan
Main sequence
program run
CHG instruction execution
Subsequence
program run
X0 OFF
ON
C0 coil
OFF
ON
C0 count value 1 2 0
CHG instruction execution
(
)
X000 K10
C0
1 scan
CHG instruction execution
Main sequence
program run
Subsequence
program run
CHG instruction execution
X0 OFF
ON
C0 coil
OFF
0
1
ON
2