Temperature PID limit

We are using a AB Compact Logix L24 ER PLC. Version 20 Logix Software.The process is heating and cooling a tank jacket. We would like to limit the P.V at a rate of 5 deg / min.
I have looked through previous posts and can’t find anything similar. The RMPS Function block looks overkill and the RLIM I am unsure about. Any input would be appreciated.
Regards
Phil

phil hughes said:

We would like to limit the P.V at a rate of 5 deg / min.

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That is hard to do without a model of your plant. It is easiest to ramp up the SP at 5 deg/min

Just build a ramp block....
You probably do not want to ramp at adding 5 degrees every minute.

So lets break it down...to seconds.
60/5=1 degree every 12 seconds or 0.5 degrees every 6 seconds or 0.25 degrees every 3 seconds.

For 0.5 degree ramp...
Use a timer and counter to build the ramprate and just add 0.5 degrees to the ramprate every 6 seconds. (The ramp rate is the SP in your PID block.)
Then use a compare function to stop the ramp...When ramprate = soak temperature then stop ramp.

in a PID this will mean the D factor goes bezirk, and the I factor will give problems, however simple thinking do not use a PID but just on/off when ramping.
and raise the setpoint slowly with your 5 c/min.

non-sense

shooter said:

in a PID this will mean the D factor goes bezirk, and the I factor will give problems,

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In motion control we ramp the set point or target position from one position to another all the time and it is done smoothly using the derivative and integrator gains.

however simple thinking do not use a PID but just on/off when ramping.
and raise the setpoint slowly with your 5 c/min.

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So how do you determine how long to have the heater on and off?

If the PID is tuned up properly then it should follow the ramp with just a little lag.