Mitsubishi MELSEC-A Series Programming Manual page 190

6. BASIC INSTRUCTIONS
The following program is written at step 0 of the main and subsequence programs.
Ladder example
Timing chart
OFF C0 count value remains unchanged.
Operation C0 count value is incremented by 1 after END (FEND, CHG) is executed during the first scan of the program
ON
depending on selected by the CHG instruction executed after X0 is switched on.
X0 ON/OFF
OFF
status
↓
C0 count value is incremented by 1 after END (FEND, CHG) is executed.
ON
(3) When the A3H, A3M, A3A, A3U, A4U and Q06H are used, execution contents
are always same.
Main sequence
program run
Subsequence
program run
X0
C0 coil
C0 count value
X000
1 scan
CHG instruction execution
ON
OFF
ON
OFF
0 1 2
6 − 78
K10
(
)
C0
CHG instruction execution
MELSEC-A