There are many industrial applications for PLCs that involve combining both timers and counters to achieve the desired results. For example, if an output is required to be energized after a 24 hour time period has elapsed, the most efficient method would be to use a timer and counter combination, Although this type of problem could be solved by using cascading timers, the program would be considerably longer than if a single counter and timer were used.

if you want you can also use the plc clock. for me this is s:40 - 42 for Time and s:39 - 37 for Date. i have slc 5/03.

I think it is easier