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MELSEC-Q
10 DEVICES
10.2.6 Edge relay (V)
(1) Definition
(a) An edge relay is a device which stores the operation results (ON/OFF
information) from the beginning of the ladder block.
Edge relays can only be used at contacts, and cannot be used as coils.
X0
X1
X10
V1
Edge relay
Stores the X0, X1 and X10 operation results
(b) The same edge relay number cannot be used twice in programs executed
by the High Performance model QCPU.
(2) Edge relay applications
Edge relays are used for detecting the leading edge (OFF to ON) in programs
configured using index modification.
SM400
[Ladder example]
X0Z1
*1
V0Z1
*1
SM400
Z1
M0Z1
K10
Z1
NEXT
K0
FOR
INC
MOV
Index register (Z1) clear
Repetition (10 times) designation
M0Z1 is turned ON 1 scan at leading edge of X0Z1
Increment Index Register (Z1) (+1)
Return to FOR instruction
When Z1=0
X0 OFF
V0 OFF
M0 OFF
ON
ON
ON
1 Scan
[Timing chart]
When Z1=1
X1 OFF
V1 OFF
M1 OFF
ON
ON
ON
1 Scan
1 scan ON at X1 leading edge
REMARK
1) 1: The ON/OFF information for X0Z1 is stored at the V0Z1 edge relay.
For example, the X0 ON/OFF information is stored at V0, and the X1
ON/OFF information is stored at V1.