Complete the user program
4.1 Add an on-delay timer to delay the start of an output
Getting started with S7-1200
42 Getting Started, 11/2009, A5E02486791-01
4.1 Add an on-delay timer to delay the start of an output
In this exercise, you will expand on the latch circuit by inserting an on-delay timer to turn on
an output after a preset amount of time.
You use the TON instruction to turn on an output (Q) after a preset delay.
The timer uses a structure stored in a data block to maintain the timer data.
You assign this data block when the timer instruction is placed in the
editor.
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When the timer turns on (IN = 1), the on-delay timer waits a preset amount of timer (PT)
until turning its output on (Q = 1). The output stays on (Q = 1) as long as the input stays on
(IN = 1).
The on-delay timer uses a data block (DB) to maintain the timer data. You assign this data
block when you insert the TON instruction onto the network.
For this exercise, you will enter a constant for the for preset time parameter (PT).
For your own application, you could also enter a Time (4-byte signed value) memory
address that stores the preset value. This would allow your user program to change the
preset value according to operating conditions, if required. You can also store the elapsed
time (ET) in a Time (4-byte signed value) memory address that can be accessed by the
other elements of your user program.
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