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4.5.2  Relation between switch operation and the LED indication 
 
(1)  Writing a program while the CPU module is stopped: 
Follow the procedure below to write a program while the CPU module is 
stopped: 
1)  RUN/STOP key switch: STOP 
RUN LED: Off ......CPU module is in STOP mode. 
  Write a program. 
2)  RUN/STOP key switch: RESET 
RUN LED: Off ......CPU module is in STOP mode. 
3)  RUN/STOP key switch: STOP 
 RUN 
RUN LED: Lit .......CPU module is in RUN mode. 
POINT 
 
 After writing a program (except for online program write), perform reset 
operation, and then place the CPU module in the RUN status. 
 When remote STOP is switched to RUN, the CPU module is not put in 
the "PROG CHECK" status but is placed in the RUN status. 
 
(2)  Latch clear operation: 
Operate the RUN/STOP key switch as follows to execute the latch clear 
operation: 
1)  Turn the RUN/STOP key switch of the CPU module from the "STOP" 
position to the "L. CLR" position several times (three or four times) to 
flicker the "USER LED" on the CPU module front. 
Normally, the LED flickers when the switch is turned several times 
(three or four times). 
When the "USER LED" flickers, it indicates that latch clear is ready. 
2)  After the "USER LED" has flickered, turning the RUN/STOP key switch 
from the "STOP" position to the "L. CLR" position again executes latch 
clear and lights up the "USER LED". 
If the "USER LED" comes on for two seconds and then goes off, it 
indicates that latch clear is completed normally. 
3)  To cancel latch clear midway, turn the RUN/STOP key switch to the 
"RUN" position to place the CPU module in the RUN state, or turn it to 
the "RESET" position to make a reset. 
 
POINT 
 
 You can make latch clear valid or invalid for each device via the device 
setting in parameter mode. 
 Instead of using the RUN/STOP key switch, you can also execute the 
latch clear operation remotely from the peripheral device. (Refer to the 
Q2AS(H)CPU(S1) User's Manual)