Specification of a Timer

Here you have to select which timer you want to use. The names go from ‘T 0’ up to ‘T 511’, but please note that not every CPU of the S7-300/400 series has got all these timers.

You really have to note that you use each timer just once. The double use of timers is an often and quite hard to find error in the PLC programming. If two persons just use one egg timer to boil eggs at different times this often turns out well, but it will be a problem if they want to do this at nearly the same time. In the cross reference list you can check whether a timer was already used. If you enter each timer that you use consequently into the symbol table you will realize immediately if you enter a timer twice by mistake, because then a symbol is displayed instead of e.g. T56.

Timers in general

S7-300 and S7-400 are registered trademarks of the Siemens AG.