Newbee's question

[Butch]

I’m new to: PLCS and to RSLogix. I’m attempting to learn on am obsolete SLC500, my problem is finding a way to setup a timer to count 15 minutes easily. I realize that this controller is limited to 10 milliseconds and -/+ 32,xxx counts. Looking for a suggestion.

[randylud]

It is called cascading timers. Done bit on first on, starts the second one and so on and so forth!

[NOP]

There's a clue in the question; "timer to count". You set a timer to time for a given period and then reset itself, you set a counter to count the timer's DN bit (ie. the number of elapsed periods) and set it's own DN bit after the number of these periods that make 15 minutes.

[gbradley]

You probably have an old fixed SLC 5/01.
If you had a Newer SLC you could set up a timer for 1 Second with a preset of 900.
But you don't have that option. ( I presume)
One option is... you can set a timer with a preset of 100, and when it is done, add 1 to a counter and reset your timer.
Now when the counter reaches 900... do your logic, and reset the counter.
Why not try this on the new simulator (http://www.plcsimulator.net/)?

Good Luck

[Butch]

Thanks, when you get as old a me, sometimes the mind goes on a holiday. I will set up the timer routine and see if I can get it to work. I know it will if I get it right.Thanks again to all of you for responding so quick and kindly. Butch