FX Series Programmable Controllers Basic Program Instructions 2
2-23
2.20 End
Basic points to remember:
-Placin
an END instruction in a pro
ram forces that pro
ram to end the current scan and
carr
out the updatin
processes for both inputs and outputs.
- Insertin
END instructions in the middle of the pro
ram helps pro
ram debu
in
as the
section after the END instruction is disabled and isolated from the area that is bein
checked. Remember to delete the END instructions from the blocks which have alread
been checked.
- When the END instruction is processed the PCs watchdo
timer is automaticall
refreshed.
Mnemonic Function Format Devices Program steps
END
(END)
Forces the current
pro
ram scan to
end
N/A 1
END
A program scan:
•A pro
ram scan is a sin
le processin
of the loaded pro
ram from start to finish, This
includes updatin
all inputs, outputs and watchdo
timers. The time period for one
such process to occur is called the scan time. This will be dependent upon pro
ram
len
th and complexit
. Immediatel
the current scan is completed the next scan
be
ins. The whole process is a continuous c
cle. Updatin
of inputs takes place at
the be
innin
of each scan while all outputs are updated at the end of the scan.
