Yaskawa Ladder Works Programming Manual - Manual (Page 14)

1.8 FALLING PULSE Instructions (OFF – PLS)
1-9
1.8 FALLING PULSE Instruction (OFF – PLS)
[Outline]
The OFF-PLS sets the value of the bit input to ON for one scan when the immediately-preceding value
of the bit output changes from ON to OFF. The designated register is used to store the previous value
of the bit output.
[Format]
Symbol : OFF-PLS
Full Name : Fall Pulse
Category : RELAY
Icon :
[Parameter]
Parameter Name Setting
Register No.
· Any bit type register (except for # and C register)
· Any bit type register with subscript (except for # and C registers)
[Program Example]
When IB00001 turns OFF, MB000101 turns ON and stays ON during 1 scan. MB000100 is used to
store the previous value of IB00001.
IB00001
MB000100
MB000101
ON
OFF
ON
OFF
ON
OFF
1 scan 1 scan
Register status of Falling pulse instruction is shown in Table 1.2.
Table 1.2 Register Status with Falling Pulse Instruction
Input Result
IB00001
MB000100
(Previous value of
IB00001)
MB000100
(IB00001 stored)
MB000101
OFF OFF OFF OFF
OFF ON OFF ON
ON OFF ON OFF
ON ON ON OFF
Notes: Case of Program Example, the instruction is used not for fall detection of MB000100 but
is used for fall detection of IB00001. MB000100 is used only for storing the previous
value of IB00001.