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4.2.
Higher-level functions
Timer and counter function
There are very many functions. In the following examples, however, we only
want to practise the most important and most frequently used functions, to be
more precise, function blocks. These are the timers and the counters.
Details about these functions will not be treated here any more. We want to
remind you only where this information can be found.
The library manager is opened in 'Resources' in 'Window' 'Library Manager'.
There you click on STANDARD.LIB. By selecting the function block TON or
CTU (
variables can easily be seen. If you want to get more detailed information, look
at Help. It has to be noted, however, that it is easier to find this information if
you look for the term "TIMER".
Task 3
Task 1 above is to be slightly modified according to practical experience in real
life.
Sometimes the sensor generates a signal for the wrong position when it detects
the edge of a correct vessel. This is to be avoided by the signal that is to be
present for at least 3 s before an alarm is given (some kind of "debounced"
signal). It is best to create a new project, e.g. testtime1.
Task 4
A ventilator starts running when the light is switched on. There is an after-glow
of 10 s when the light has been turned off (new project).
Now on to the counter:
Task 5
The vessels in the example above (Figure 123) have been filled, closed by
means of the lid and they are counted by a photoelectric sensor when they
arrive at the packing station. The package consists of 12 vessels. One output
(e.g. full: lamp) is set when the preset value 12 has been reached.
Implementation using up counter
Implementation using down counter
What is to happen when the package is full?
R
further below) the meaning of the inputs and outputs and/or types of
Exercises
4-5
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