I need to make a temperature Controller where in I need to supply heating parameters like: Heating rate (Deg/Hr), Soaking Temperature (Process Temperature), Soaking Time (Time where soaking temperature would need to be stable), Cooling Rate (deg/Hr).

May I know where to start with? I have been experimenting with the Compact PID, however, most of the time, the reading overshoots for +10Deg C, will need a very accurate PID tuning.

Also I don't know where to adjust in Compact PID if I need to input a temperature rate value (DegC/Hr).

Thanks for anyone who can help me out.

Hello ChrisJoan,

actually you use the PID_compact.

In my opinion is better you use the PID_Temp.
This is especcially for temperature regulation with all challenges of the temperature regulation.
I use this for temperature applications and it works properly.

Which PLC and which software do you use?

This suggested solution is for the 1200/1500.

regards
CaOd

Hello ChrisJoan;

Following CaOd's suggestion: for further information on PID_TEMP, have a look at the following application example:

Multizone control with Simatic PID_TEMP:

https://support.industry.siemens.com/cs/us/en/view/109740463

As mentioned, this is a solution for S7-1200 and S7-1500 CPUs.

For S7-300 and S7-400 PLCs, you can look up FB 58 TCONT_CP for temperature control.

https://support.industry.siemens.com/cs/us/en/view/596948

Our friend Hamid Hosseini proposes a video example of the use of FB 58 in this discussion:

https://support.industry.siemens.com/tf/us/en/posts/fb58-for-temperature-control-application-which-parameters-are-needed-to-pass-to-get-appropriate-output-from-the-function-block/197716/?page=0&pageSize=10

Hope this helps,

Daniel Chartier 

Sorry, I forgot to include my HW and SW:

CPU1212C / SM1231 TC / KTP700 Basic

TIA Portal V15 Update 4

I tried PID_Temp, its better than the PID_Compact, I have problems updating the setpoint value on the later. In PID_Temp, its smooth in recognizing my new setpoint.

I am curious on where to adjust the PID Parameters, when I need to heat a certain material in a very gradual manner, like 100DegC/per Hour and the final temp is 500DegC.That means I should reach 500DegC in 5 Hrs.

Which PID parameters do I adjust and I need to adjust it via my HMI.

Thanks

Hello ChrisJoan,

the setpoint for the PID should you calculate externally.

Calculate the setpoint as a linear function.
Then can you also check that the actual value and the setpoint have a maximum difference.
If the difference between the setpoint and the actual value to high, then can you stop the ramp of your setpoint.

to ramp the setpoint you can use the function RampFunctiion. You can find this function uinder Technology - PID Control - Auxiliary functions - Ramp function.
There you can adjust the maximum slew rate for your setpoint.- e.g. 100 degree/ hour.

regards
CaOd

 Hi CaOd,

Thanks for sharing this information, I am still new to PID, may I know where to put this block? Will be in series with the input of my PID_Temp Block?

CaOd

Hello ChrisJoan,

the setpoint for the PID should you calculate externally.

Calculate the setpoint as a linear function.
Then can you also check that the actual value and the setpoint have a maximum difference.
If the difference between the setpoint and the actual value to high, then can you stop the ramp of your setpoint.

to ramp the setpoint you can use the function RampFunctiion. You can find this function uinder Technology - PID Control - Auxiliary functions - Ramp function.
There you can adjust the maximum slew rate for your setpoint.- e.g. 100 degree/ hour.

regards
CaOd

Hello ChrisJoan,

your target temperature is the input value at the Ramp-function.
the output of your Ramp is connect to the setpoint of your PID.

Then you have no problems adjusting the slope of your desired temperature curve with the parameter SlewRate.

Otherwise can you also use the function LGF_Ramp from the 

Library of general functions (LGF) for SIMATIC STEP 7 (TIA Portal) and SIMATIC S7-1200 / S7-1500

regards
CaOd

 Hi CaOd,

The Ramp Function, greatly improve my slope and the overshooting is not that high anymore. Thanks for this idea.

I came across RAMP_SOAK function blocks for S7-300, is this applicable in S7-1200? This block is what I am looking for to simplify my project.

Thanks

CaOd

Hello ChrisJoan,

your target temperature is the input value at the Ramp-function.
the output of your Ramp is connect to the setpoint of your PID.

Then you have no problems adjusting the slope of your desired temperature curve with the parameter SlewRate.

Otherwise can you also use the function LGF_Ramp from the 

Library of general functions (LGF) for SIMATIC STEP 7 (TIA Portal) and SIMATIC S7-1200 / S7-1500

regards
CaOd

Hello ChrisJoan,

the function LGF_Ramp is nearly the same like RMP_SOAK.

Please look at the description in the manual of LGF (see last link).
There you can see at page 126 a diagram which showing the function of LGF_Ramp.

In my opinion you can use the LGF_Ramp and have the right function for your application.

regards
CaOd