Timers

Using AB RS Logix5 software, I am trying to increment a temperature 200 degrees per hour ten times. In other words, bring something up to 2000 degrees over a span of ten hours and hold there. I am trying to figure out a way to do this without using ten timers! I am a electrical technician who modifies programs, not a programmer. Thanks in advance.

I've never programmed in Logix5 before, but in 500 I would use one timer that counted to an hour and then incremented a counter upon being done, then reset itself and started over. Every time the counter counts up, you can increase your temp set point. Once it reaches 10, you're at 10 hours with your final set point and you can reset the counter for the next startup.

Welcome to the forum.

you can use a timer with a 1 second time base with the preset of 3600.
then the timer times out - increment the system to the next temperature level.
the timer can reset itself in the timing logic or use the reset command.

I do have a question,
what starts the timer ?
what turns off the timer logic?

regards,
james

If you wanted a smooth set point change rather than steps you could do something like this: Though as pointed out previously there is more to consider. What happens if the operation is paused during the ramp, or faults and has to be reset etc.

I want the timer to start after the actual temperature is compared and found to be less than 2000 deg. F. I will take that actual temperature and add 200 deg. to it That is the point that the timer will start. I will leave it at that temperature for an hour. When the timer has timed out, if I am still below 2000 deg. then I will add 200 and run at that new temperature again . This will continue until I reach 2000 deg. After being at 2000 deg. for 2 hours, I will end the cycle

Don't forget to limit the setpoint to 2000. Since you're starting at a variable temperature and adding 200 degree increments, you could potentially go from 1999 to 2199 (worst case). Use a GRT and MOV to check and limit the result of the addition step.