D-54
Timing Diagram:
X0
M0
Y0
a scan time
LD
M0
Load the contact A of M0
SET Y0
Y0 latched (ON)
Mnemonic Function
PLF Falling-edge
output
Operand
X0~X17 Y0~Y17
M0~M159 T0~15 C0~C7 D0~D29
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Explanations:
When X0= ON
→
OFF (falling-edge trigger), PLF command will be executed and M0 will send the
pulse of one time which the length is the time for scan one time.
Program Example:
Ladder diagram:
Command code:
Operation:
X0
M0
PLF
M0
Y0
SET
Timing Diagram:
a scan time
X0
M0
Y0
LD
X0
Load A contact of X0
PLF M0
M0 falling-edge output
LD
M0
Load the contact A of M0
SET Y0
Y0 latched (ON)
Mnemonic Function
END Program
End
Operand
None
Explanations:
It needs to add the END command at the end of ladder diagram program or command program. PLC
will scan from address o to END command, after executing it will return to address 0 to scan again.