PID Temperature Controllers - Article

Tecnologic UK supply a range of PID temperature controllers for use in a wide variety of industrial applications. We specialise in providing high quality instruments at reasonable prices, as well as providing technical support to ensure you have a PID temperature controller that meets your needs and is functioning correctly.

Here we examine how PID temperature controllers work, where you might need PID temperature control, and how to go about obtaining a Tecnologic PID temperature controller for your application.

PID Temperature Controllers – click here to view our range of products

What is a PID Controller? 

A PID controller is a microprocessor unit which closely controls an output between certain limits. It can be used to control an output signal for any purpose. For instance some PID controllers are used to control the physical position of something, such as the degree to which a valve is held open. However, temperature control is one of the most common applications for a PID controller and we will focus on PID temperature controllers here.

A PID temperature controller works by measuring the current temperature, comparing it to the required temperature to generate an error signal, and altering the output to bring it closer to the target. The unit is therefore constantly adjusting the output according to how close it is to the set point required.

PID stands for Proportional Integral Derivative, with each of the 3 elements referring to a different way of processing the error signal in order to modify the output. It is the combination of these three processes which forms the overall algorithm of the controller. And it is the quality of this algorithm which determines the overall accuracy a particular PID controller.

In very broad terms, the three elements consider different aspects of the error with respect to time. The Proportional element (P) looks at the current error, a fairly simple comparison between the target temperature and the actual temperature. The Integral element (I) looks at the pattern of previous errors over time. The Derivative element (D) looks at how fast the error is changing, to come up with a prediction of future errors.

The three elements are then combined to produce an overall result which tells the processor whether to alter the output and by how much.

The formula used for calculating each of these elements can be more or less sophisticated to take into account different types of error situation. The more sophisticated the algorithm the better quality control will be achieved.

The main alternative to PID temperature control is an On/Off control which works like a thermostat. With a thermostat control the control source (heating or cooling device) would be either 'On' whenever the error goes outside its specified limits, or 'Off' when it is within its specified limits. This inevitably results in undershoot and overshoot, with very little time actually at target temperature. For example, for a target temperature of 200 degrees C, an On/Off control could produce temperature oscillations between 195 and 205 degrees. A PID temperature controller, by contrast, would hold the temperature at 200 degrees with very little if any fluctuation. It does this by anticipating things like undershoot and overshoot, heat up and cool down times and inertia of the control source.

Generic PID temperature controllers are “process unaware”. That is, they are trying to maintain a target temperature but with no consideration of the process which that temperature control is being used for, or the aspects of that process which are likely to interfere with the desired temperature. The accuracy of a PID temperature controller can be improved by including some information about that process into the overall algorithm. In other words, the controller can be made more intelligent, and therefore more accurate, by giving it some additional context about the situation it is controlling.

Tecnologic’s PID temperature controllers allow this process-specific information to be used as part of the control process, by allowing various parameters to be set via its configuration control software. It is this ability to easily configure a Tecnologic PID temperature controller which transforms a generic control unit into a high performance device which is tailored to the specific context of use and which can then achieve extremely high levels of accuracy.

Our PID controller configuration software also allows us to provide high quality temperature controllers at extremely competitive prices. Instead of needing to build bespoke (and therefore expensive) controllers for each customer, we can provide generic (and therefore low cost) hardware which can then be highly configured using separate software.

For more general information on PID controllers click here.

What Applications Need PID Temperature Control?

PID temperature control is required in any industrial process where it is critical for temperature to be maintained within strict limits for any reason.

The number of industrial applications are vast, but here are a few examples:

  • Laboratory incubators used for working on DNA
  • Industrial ovens
  • Lab equipment
  • Environmental chambers
  • Autoclaves
  • Smoke machines
  • Catering water baths
  • Packaging machinery

Tecnologic PID Temperature Controllers

Tecnologic make a range of PID temperature controllers, from basic entry-level units through to highly customisable devices giving the user a high degree of control over more complex processes. For instance, our higher end models allow the user to specify multi-segment processes whereby temperature is automatically changed to a different set point for a period of time, and to respond to multiple events during the process.

Many of our control units are bought by equipment manufacturers who want to incorporate a PID controller into a more specialised piece of kit. For this reason, some of our controllers have their own displays which can be slotted into a panel, while others are designed to feed into the user’s own display.

Most of our PID controllers are panel mounted, while some are din rail mounted for use inside panels. In addition, all our units have excellent build quality, are easy to program and have UL approval.

Our PID temperature controllers are competitively priced when compared to other instruments offering similar performance. In the event that one of our standard products cannot be adapted for your process, we can also produce custom PCB solutions for specific customer requirements.

For more information about of our range of PID temperature control units, please click here.

Alternatively, contact us to discuss your requirements.  We will assess your needs and application over the phone or email and then make recommendations from our range to match your requirements. We will always aim to specify the instruments with the best performance to cost ratio and where possible from our stocked range. If more information is needed a site visit can easily be arranged.

Tags for this article: PID, Process Control, PID Controller,

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