If you are looking for a clock with a period of 10 seconds (frequency is 1/10 Hz) then the following circuit will work.
If the Set Value of the COUNTER, 10SecClk, is 10, then 10SecClk will go active for 1 scan time every 10 seconds.
The RSctr (counter reset) should be placed
immediately BEFORE the rung that causes the counter to decrement.
This ensures that the 10SecClk will be active for a full
scan of the ladder logic.
If the order of the ladder logic rungs is switched, then
the 10SecClk will not be seen by the ladder logic
10SecClk 10SecClk
-----||--------------------------------------(RSctr)
Clk:1s 10SecClk
-----||---------------------------------------(CTR)
If you are looking for a 10 second time period to be used as a delay, time limit, minimum ON time, then I'd use a TIMER.
Gary D
