What Is PID Tuning & How Does It Work?

Posted by Stephan Sommer in on 14 February 2014

To achieve the best level of process control it is necessary to tune PID controllers, this can be done in a number of ways.

Manual PID Tuning

Controllers will enable manual PID tuning meaning the P, I and D variables must be manually calculated by the engineer and set using the controller menu. This requires a reasonable level of knowledge and understanding from the user to be able to carry out the calculation. Often manual PID tuning will still require some trial and error testing to achieve peak efficiency. Manual tuning can be extremely time consuming compared to the alternatives.

PID Auto-Tuning

Most modern PID process controllers will support auto-tuning (also known as self-tuning) of the PID settings. Typically the way this works will depend on which manufacturer’s product you are using, but commonly they use a rule based calculation in the same way that an experienced engineer tuning the device manually would. Auto-tuning can either take place at the set-point or with some controllers it occurs as the load is being heated up from the ambient temperature.

PID-Tuning-Tune-At-Setpoint

Typical PID Tuning at Setpoint

 

More recently, controllers have introduced a number of options for auto-tuning PID settings. These allow the settings to be more closely aligned to a specific application’s requirements for example prioritising the minimisation of overshoot over the time it takes to reach the set-point.

Users are advised to refer to their manufacturer’s technical support if they have specific application requirements which they are unsure of.

Find Out More

  • Discover more temperature control terminology in our Glossary

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