What is a PID controller in a pellet grill?

A PID controller is a tool used for precise temperature control. People have been using them, in various applications, since their invention 30+ years ago. It has several features that make cooking with a pellet grill easier and more consistent than without it. One of the best applications for the PID controller is for smoking meat low and slow

PID controllers are able to maintain extremely accurate temperatures, which allows you to set your smoker/grill cook temp and walk away. They also provide a lot of information, such as current meat temp, cooking time, humidity levels in the grill, etc in the modern versions

PID is an acronym for Proportional-Integral-Derivative. This is an algorithm often used to control industrial systems where the output needs to be kept very close to a specific set point, especially processes with a distinct lag between cause and effect, which are most often seen in temperature control applications.

In this article, I will explain how I use a PID controller with a pellet grill, and how it has helped me to be able to walk away from my smoker.

I am hoping that information like this will make everyone better cooks, more consistent cooks, and ultimately save us some heartache along the way.

What is a PID controller in a pellet grill?

A PID controller works by using feedback to estimate and maintain the temperature of your smoker. It does this by cycling on and off the heating element (in this case, a pellet grill).

A regular control system has two parts: one part that determines what set point to use, and one part that acts on the feedback to estimate how far off you are from your set point.

A PID controller has three parameters (Kp, Ki, Kd) which determine how it reacts. The three parameters make up a mathematical formula or algorithm like this: Here I is the integral of the error over time, and D is the derivative of the error over time.

The control parameters (Kp, Ki, Kd) are determined by trial and error to get you close to your set point. The settling time tells how quickly it converges on your target temperature.

I use a short settling time because it reaches my target temp pretty fast after cycling on.

The maximum temperature differential setting tells the controller how far away from your target temp you can be before it will begin to cycle on or off.

I use a small maximum temperature differential because I want my grill to stay as close to the setpoint as possible, not fluctuate above and below my set point temperature for very long.

Why do you use a PID? Is it for better food?

Yes, using a PID controller helps you cook better food. It can hit the target temp and hold it there for hours without constantly fiddling with the pellet grill controls to try and keep an even temperature.

Use a PID to maintain your smoker’s temperature more precisely and because it works.

How long did it take you to get your controller set where you wanted it?

Should you upgrade to a PID controller?

I started with a cheap controller that had only an on/off switch. It took me a few years to realize how valuable a thermostat is for controlling temperature, and how poorly my old controller was working for this task. In 2019 I upgraded to the PID controller because there were some features it offered that I wanted, like Bluetooth connectivity. One of the benefits was that it had a power switch (something my other controller didn’t have) so it would turn on and off with the pellet grill.

I use a PID because it is an excellent way to control temperature. It works for me.

Conclusion

PID controllers are used to stabilize the temperature in many applications. For example, it is the central controller for most of the spacecraft that we send out to explore our solar system. They are found everywhere where precise control needs to be available.

Setting up your own PID controller is easy if you have a pellet grill with an accurate thermometer. You just have to set the desired temperature, set up a few parameters for heat output on your heating element(s), and wait until the controller tells you what the current temperature is, how it’s changing, and whether or not it has reached your desired temperature.