Chapter 5 Program Configuration and Operation Method
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5.5.5 Data Latch Area Setting
When PLC stops and restarts the data required for operation or the data occurred during operation, if you
want to keep and use those data, data latch can be used and it is available to use a certain area of some
data device as latch area by parameter setting.
The below shows the features for latch device.
Device 1
st
latch
2
nd
latch
Features
P
X
X
Image area to save the state of I/O device
M O O
Internal
device
area
K
X
X
Device keeping the device state during power shutdown
F X X
System
flag
area
T
O
O
Timer related area (Bit/words both)
C
O
O
Counter related area (Bit/words both)
S
O
O
Relay for step control
D
O
O
General words data save area
U
X
X
Analog Data Register (latch disabled )
L X X
High speed link/P2P Service state device of communication
module (latch enabled)
N X X
P2P Service address area of communication module (latch
enabled)
Z
X
X
Index dedicated Register (latch disabled)
R
X
X
Flash memory dedicated area (latch enabled)
Notes
1) K, L, N, R devices are basically latched.
2) K, L, R devices operate like the 1
st
Latch that clears data by using Overall Reset or the CPU
module D.CLR switch.
3) For more information, refer to the Online section of the
XG 5000
user’s manual.
