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Pilot Light indicator light typically used represent condition a
machine process.
The PLC scan involves updating the status inputs, executing
the user program, performing diagnostic and communication
functions, and updating the status outputs.
New Position
Old Position
Plug-In Unit
.
PLC Scan
R
e
a
d
Inputs
U
p
d
a
t
e
O
u
tputs
Execu
t
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P
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o
g
r
a
m
Diagnos
t
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c
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Communi
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o
n
Plug-in Busway Busway that incorporates plug-in units, called bus plugs, to
allow loads distributed over the length the run. PLC scan is
repetitively executed.
RUN Pilot Light On
Motor Running Motor Stopped
STOP Pilot Light On
PLC Scan complete execution cycle programmable logic controller
