Specifications

4 Hardware-Independent Programming

4.3 Programming of "clock bits"

Programming Guideline for S7-1200/1500

V1.2, Entry ID: 81318674

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4.3 Programming of "clock bits"

Recommendation

For the programming of clock memory bits, the hardware configuration always has

to be correct.

Use a programmed block as clock generator. Below, you can find a programming

example for a clock generator in the SCL programming language.

Example

The programmed block has the following functions. A desired frequency is

specified. The “Q” output is a Boolean value that toggles in the desired frequency.

The “Countdown” output outputs the remaining time of the current state of “Q”.

If the desired frequency is smaller or equal 0.0, then the output Q = FALSE and

Countdown = 0.0.

Period: 2 seconds

Frequency [Real]

Q [Bool]

Countdown [Time]

0.5

T#0S_703MS

TRUE

Note

The complete programming example is available for free download in the

following entry:

http://support.automation.siemens.com/WW/view/en/87507915