Pls, Plf - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
7.12

PLS, PLF

Outline
When PLS instruction is executed, an applicable device is activated during only one operation cycle after a
drive input turns ON.
When PLF instruction is executed, an applicable device is activated during only one operation cycle after a
drive input turns OFF.
For example, when PLC mode is changed in the way "RUN → STOP → RUN" while a drive input remains
ON, "PLS M0" operates, but "PLS M600 (backed up by the battery against power failure)" does not operate
(when the PLC mode switches from STOP to RUN) because the status of M600 is latched even while the
PLC is in the STOP mode.
1. Instruction format
PLS
Pulse
PLF
Pulse Falling
2. Applicable devices
Bit Devices
Instruc-
System User
tion
X Y M T C S D .b KnX KnY KnM KnS T C D R U \G
PLS
1
PLF
1
: Except special auxiliary relays (M)
1
: This function is supported only in FX
2
Explanation of function and operation
1. PLS instruction (rising edge pulse)
Circuit program
X000
In the figure above, M0 is ON during only one operation cycle when X000 changes from OFF to ON.
2. PLF instruction (falling/trailing edge pulse)
Circuit program
X000
In the figure above, M1 is ON during only one operation cycle when X000 changes from ON to OFF.
Mnemonic Operation Condition
Basic Instruction
−
PLS
Mnemonic Operation Condition
Basic Instruction
−
PLF
→ For the number of instruction steps, refer to Section 7.15.
Digit Specification
/FX
3U 3UC
List program
0000 LD
PLS M0
0001 PLS M 0
List program
0000 LD
PLF M1
0001 PLF M 1
Continuous
Operation
Pulse (Single)
Operation
Continuous
Operation
Pulse (Single)
Operation
Word Devices
Special
System User Index
Unit
V Z Modify K H
PLCs.
Timing chart
X000
PLS
instruction
Timing chart
X000
PLF
instruction
7 Basic Instruction
7.12 PLS, PLF
Others
Con- Real Charac-
Pointer
stant Number ter String
E " "
2
2
ON
X000
ON during
one operation
M 0
cycle
ON
X000
ON during
one operation
M 1 cycle
219
1
2
3
4
5
6
P
7
8
9
10