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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
[Ladder example]
SM400
X0Z1 V0Z1
SM400
*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.
[Timing chart]
When Z1=0
When Z1=1
(3) Precautions
The edge relay of the same number cannot be set only once in a program.
X0
X1
X10
V1
Figure 9.16 Edge relay
.
MOV KO Z1
FOR K10
*1
*1
M0Z1
INC Z1
NEXT
ON
X0
OFF
ON
OFF
V0
ON
M0
OFF
1 scan
X1
OFF
V1
OFF
M1
OFF
Figure 9.17 Application example and timing chart of the edge relay
Stores on/off information of
X0, X1, and X10.
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)
Returns to FOR instruction.
ON
ON
Turns on for 1 scan by rise of X1.
ON
1 scan
CHAPTER9 DEVICES
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