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timohei.net / My Courses / Production Automation Project / Siemens S7 How-to / Clock Pulses /

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Clock Pulses

In Siemens S7-1200 PLC's, any M area byte can be used for generating clock pulses. In the example below byte MB100 is used as in most cases the default byte M0 is already used for different pusrposes by the application.

Open Properties of the PLC

From tab General select Clock memory or System and clock memory, depeding on your TIA Portal version

Check Clock memory and type in an address for unused M area byte

Different pulse frequencies are generated at individual bits M100.0-7 according to the table below.

Muistibitti	M100.7	M100.6	M100.5	M100.4	M100.3	M100.2	M100.1	M100.0
Jakso [s]	2.0	1.6	1.0	0.8	0.5	0.4	0.2	0.1
Taajuus [Hz]	0.5	0.625	1	1.25	2	2.5	5	10

Load the changes you just made by downloading Hardware configuration.

If clock pulses do not work make sure you do not have the byte you just selected for clock pulses in other use.

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