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CHAPTER9 DEVICES
9
9.2 Int
ernal User Devices
9.2.6 Edg
e relay
(V)
9.2.6 Edge relay (V)
(1) Definition
The edge relay (V) is a device in which the on/off information from the beginning of the ladder block.
Contacts only can be used. (Coils cannot be used).
(2) Applications of the edge relay
The edge relay can be utilized to detect the leading edge (off to on) in programs configured using index
modification.
*1: The on/off information for X0Z1 is stored in the V0Z1 edge relay.
For example, the on/off information of X0 is stored in V0, and that of X1 is stored in V1.
(3) Precautions
The edge relay of the same number cannot be set only once in a program.
Figure 9.16 Edge relay
Figure 9.17 Application example and timing chart of the edge relay
X0
X1
X10
V1
Stores on/off information of
X0, X1, and X10.
Returns to FOR instruction.
SM400
X0Z1
V0Z1
SM400
*1
*1
MOV KO Z1
FOR K10
M0Z1
INC Z1
NEXT
Clears index register (Z1).
Specifies the number of repeats (10 times).
Turns on M0Z1 1 scan,
followed by rise of X0Z1.
Increments index
register (Z1). (+1)
[Ladder example]
[Timing chart]
When Z1=0
When Z1=1
X0
M0
V0
X1
M1
V1
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
1 scan
1 scan
Turns on for 1 scan by rise of X1.
