Filter
Top Products
FX Series Programmable Controllers Basic Program Instructions 2
2-23
2.20 End
Basic points to remember:
- Placing an END instruction in a program forces that program to end the current scan and
carry out the updating processes for both inputs and outputs.
- Inserting END instructions in the middle of the program helps program debugging as the
section after the END instruction is disabled and isolated from the area that is being
checked. Remember to delete the END instructions from the blocks which have already
been checked.
- When the END instruction is processed the PLCs watchdog timer is automatically
refreshed.
Mnemonic Function Format Devices Program steps
END
(END)
Forces the current
program scan to
end
N/A 1
END
A program scan:
• A program scan is a single processing of the loaded program from start to finish, This
includes updating all inputs, outputs and watchdog timers. The time period for one
such process to occur is called the scan time. This will be dependent upon program
length and complexity. Immediately the current scan is completed the next scan
begins. The whole process is a continuous cycle. Updating of inputs takes place at
the beginning of each scan while all outputs are updated at the end of the scan.