How can I wire a PID controller, heating element and thermocouple?
For example, I wish to heat my solution up to 80 degC and the heating element will automatically shut off once it reaches 80 degC. When the solution is below the desired temperature, the PID controller will trigger the heating element automatically to reach back to the desire temperature.
Dear Wei Jian,
Unfortunately, your question brings up 2 more questions. could you elaborate on these? if so, I (or others) might be able to help you better:
The questions:
A) What is your main required task? Is it (tight or general) setpoint tracking,minimum temperature guarantee, energy optimal or time optimal control? This will influence the components/type of control:
* For minimum temp guarantee: Use an on/off controller with a dead band and early shutoff to take into account the delay/overshoot.
* For time optimal control without overshoot: Use a PI(D) controller and control the heating power using a PWM signal (continuous) controlled by controller .
* For energy optimal control//setpoint tracking: Identify the dynamics in detail, and use a model based controller to track your setpoint as close as possible (check literature on model predictive control).
B) Also: Do you already have a specific hardware in mind? Since the wiring will depend on the type of thermocouple, PID controller & heating element you use. Some PID controllers can switch high power heaters directly, others will need (solid state) relays . Some can use thermocouples as a direct input, others will need a conversion circuit.
Could you first answer this questions? With this information, i (or others reading this question might be able togive more details on your wiring!
Kind regards,
Joachim
Phd student, Mechanical department, KULeuven
I wish to keep my temperature constant through out the experiment. Therefore, I use a PID controller to control my heating element to on and off by itself.
Secondly, I have already have a specific hardware in my mind. I bought a PID controller which can connect to a K type thermocouple, a RSS which use to step up my current because the PID controller i bought, the current is too small and I use an immersion heater as my heating element.
Regards,
Wei Jian
As per standard terminology. your heating element is the plant, thermocouple is the feedback sensor, PID controller is the controller. Then reference input voltage = thermocouple output voltage corresponding to your desired temperature. Refer to the canonical form of feedback control system.
hi
pid controllers usually have ssr output, and using one ssr(solid state relay )you can adjust temp precisely
please have a look at attached file
regards
Yes, ,t can be on / off mode.You will connect the termocouple as PV (process value/feedback). Your output will be connected to heating element ( I prefer to use extra relay for output). Your reference will come from outside as analog,digital or from keypad of controller you bought..
Please refer to these articles:
https://www.researchgate.net/publication/313576646_From_PID_to_Nonlinear_State_Error_Feedback_Controller
https://www.researchgate.net/publication/312046377_Improved_Sliding_Mode_Nonlinear_Extended_State_Observer_based_Active_Disturbance_Rejection_Control_for_Uncertain_Systems_with_Unknown_Total_Disturbance
https://www.researchgate.net/publication/309655805_On_the_Improved_Nonlinear_Tracking_Differentiator_based_Nonlinear_PID_Controller_Design
Article From PID to Nonlinear State Error Feedback Controller
Article Improved Sliding Mode Nonlinear Extended State Observer base...
Article On the Improved Nonlinear Tracking Differentiator based Nonl...
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