Counting running time for 3 pumps

Hello everybody,
I'm working on Siemens step 7, and I need to find how can I count running time for each pump and compare this time to pick the pump with low time. Any ideas will be helpfull, thanx

Depending on resolution you need, adding up a 1 with a fixed interval works well.

We using a 1 minute resolution, have a timer that pulses every minute and add 1 to to minute run time. When this reaches 60 we add 1 to the current run time and replace minute run time with a 0.

Use advanced search of the forum for 'pump', 'titles only'.