How Do Temperature Controllers Work?

Controlling the temperature of a system is an essential process for many areas of industry. From air conditioning systems and refrigerators to ovens and greenhouses, temperature control systems are everywhere. When these systems don’t work, temperatures can fall out of range, negatively affecting work environments, equipment and products. But how do these systems work, and what kinds of systems are available? That’s precisely what we’ll address in this article.

Table of Contents

What Is a Temperature Controller?
How Do We Control Temperature?
Types of Temperature Controllers
Why Temperature Controllers Are Important
Temperature Controller Applications
Call Global Electronic Services for Temperature Controller Repair

What Is a Temperature Controller?

A temperature controller, at its most basic, is a device used to control the temperature in a system. These devices are essential in any situation where an object or system must be heated or cooled to remain at a specific temperature.

All controllers consist of inputs and outputs — these are explained in more detail below:

    • Inputs: Inputs are the signals that enter the system. In basic, human-controlled operations, an input would be a person turning up the dial for a cooling system. In more advanced systems, however, an input would be the actual temperature of the system measured using temperature sensors.


  • Outputs: Every controller has an output or an effect that it produces. Typically, controllers have one or more outputs. For example, a typical home thermostat will have heating and cooling outputs. However, more sophisticated systems may have additional outputs, such as an alarm or recording system.

In a temperature control system, the controller processes the inputs and sends signals to an amp that produces the outputs. The types of inputs and outputs and the steps involved between them vary based on the specific type of temperature controller in use.

How Do We Control Temperature?

There are two basic types of temperature control — open-loop control and closed-loop control. The most simple form of control is open-loop control. It applies continuous cooling or heating based on the input from the user and doesn’t account for the actual temperature output. As an example, older cars have basic temperature control systems that allow a user to heat or cool the car as desired. Setting the car to blast the heater will help warm the car on a cold day but will make the car unbearably hot on a warm day.

The issue with open-loop control systems is that the system is not set to maintain a specific temperature — just a specific output. If a user wanted to maintain a specific temperature with an open-loop system, they would need to monitor the system continuously and adjust the output accordingly. Even then, the potential for human error would make this system extremely inaccurate for processes that required constant, precise temperatures. As a result, almost all industrial temperature control systems use a closed-loop system.

Closed-loop control is a more sophisticated system of temperature control. In this system, temperature control is automated. The temperature controller uses pre-set parameters to carry out functions. Some typical parameters temperature controllers work with include:

    • Process Variable: In a temperature control system, the variable being controlled is the temperature. This is the process variable. This variable is constantly measured in a closed-loop control system and used as the input.
    • Setpoint: A setpoint is a target value. This target value is set by the operator, and the purpose of the controller is to try and match the process variable to the setpoint at all times. For example, if an operator sets the setpoint to 75 degrees, the controller will apply heating and cooling as necessary to keep the environment at this temperature.
    • Deviation: If there is a difference between the process variable and the setpoint, this difference is known as the deviation. This deviation is used to determine how the controller will respond to reach the setpoint. If the deviation is negative, the controller will apply heat to bring the process variable up. If the deviation is positive, the controller will reduce heat or turn on a cooling system to bring the process variable down.
    • Manipulated Value: A temperature control system responds to a deviation by altering its output. This is known as the manipulated value. For example, the amount of heat applied to a system to increase the process variable would be the manipulated value.


  • Alarm Value: In some systems, one potential output is an alarm. In these systems, if the system meets some given condition, an alarm will go off to alert the user. As an example, a system may have a setpoint of 100 degrees and have a setting that causes an alarm to go off if the system temperature deviates more than 10 degrees in either direction.
  • Break Indicators: Temperature controllers also usually have a self-monitoring system that detects when a potential problem has occurred. For example, the controller may detect if a sensor reading has suddenly changed or has not fluctuated for a certain period and alert the system user of a potential sensor break.

An excellent example of a closed-loop system is a car with climate control. Instead of setting the vehicle to heat or cool, the user inputs the desired temperature and the car automatically adjusts the input of heating and cooling to maintain that target temperature.

Types of Temperature Controllers

Closed-loop control systems are most commonly used today, and there are several kinds of closed-loop systems. In general, there are three types of temperature controllers manufacturing companies use — on/off, proportional and PID. How do these industrial temperature controllers work? Find out below:

    • On/Off Controls: This kind of temperature control is the most simple and least expensive type. In this system, the temperature inputs are monitored continuously, but the output is either completely on or completely off. When the temperature reaches a specific level, the controller detects this and signals the heating or cooling system to turn on or off. The most common example is a residential thermostat. If the temperature of the house falls outside the setpoint range, the thermostat signals the heating or cooling systems to turn on, then turns them off when the house reaches the setpoint range again.
    • Proportional Control: Proportional control systems are designed to prevent the temperature from falling out of the setpoint range. Unlike on/off systems that respond only when the temperature drops outside of the setpoint range, proportional controls raise or lower the amount of heating or cooling applied to a system as the temperature enters the upper or lower limits of the setpoint range. The range within which the proportional controls increase or decrease the heating or cooling system is called the proportional band. When the temperature enters the upper or lower limit of this proportional band, the control system turns the heating or cooling system on to bring the temperature back to the desired range. This ensures that the temperature of the system is kept relatively stable


  • PID Control: PID stands for proportional integral derivative, indicating that this control system combines proportional, integral and derivative control. Like proportional control, a PID system operates on a proportional band that allows it to adjust the amount of heating or cooling applied to the system at any given time. The primary difference is that PID systems use more data to control temperature intelligently. The PID system does this by using an integral value to analyze recent trends and a derivative value to determine how to react to these trends. This data, combined with the proportional band, allows the PID system to create an algorithm to adjust the temperature accurately and effectively.

On/off systems are most often used in applications where precise temperature control is not necessary. However, if precise control is needed, such as in healthcare and manufacturing applications, proportional and PID control systems are most commonly used.

Why Temperature Controllers Are Important

While most people are familiar with temperature controllers in their homes and cars, temperature control is also essential in industry. Temperature control plays the following roles in industry and manufacturing, specifically:

    • Material Setting: Temperature control is critical for proper product formation. Many materials require a specific temperature range in order to melt or set properly. If the temperature falls outside of this range, products may come out of the process with improperly adhered coatings, weakened base materials or compromised parts. This, in turn, can increase costs for manufacturers as they have to redo any faulty work while also checking their equipment and processes for failures.
    • Equipment Maintenance: Many pieces of manufacturing equipment operate within specific temperature parameters. If the equipment regularly operates outside of these parameters, however, the equipment should be checked for signs of malfunction. Temperature controllers can help alert users when machines begin to show signs of damage, which helps with equipment maintenance.


  • Environmental Conditions: Not only is temperature control important for products, but it is also vital for employees. Temperature control helps keep working conditions within safe ranges so that employees can work in relative comfort without risking their health or safety.

These capabilities make temperature controllers vital in a wide range of applications.

Temperature Controller Applications

Temperature controllers are used in a variety of industries to manage various aspects of manufacturing processes and operations. Some of the most common applications of temperature controllers in industry include the following:

    • Heat Treating Applications: Temperature controllers are often used in ovens and heat-treating applications. In these operations, the temperature controller is connected to a thermostat as the input and a heater as the output and maintains a set level of heat to achieve the desired results for the material application. Some examples of this include kitchen ovens, ceramic kilns, boiler systems, heat exchangers and furnaces.
    • Packaging Applications: Many packaging machines use temperature controllers to handle packaging materials properly. Machinery that works with seals, glues, shrink wraps, labels and other materials used in packaging must often operate within a specific range of temperatures over a set period to achieve proper sealing. If the machinery does not work as intended, packaging may be incomplete or poorly sealed, potentially resulting in product loss or damage. Temperature controllers help by ensuring that these operations proceed as intended to achieve a high-quality package seal.
    • Plastic Applications: Plastics are used in a wide range of industries, from consumer products to electronics to the healthcare industry. Manufacturers generally form plastics into final products through the use of heating and cooling. Plastic extrusion and injection molding machines, thermo-folding machines, portable chillers, hoppers and dryers all rely on careful temperature control to achieve optimal results. In all cases, temperature controllers are used to accurately and precisely monitor operating temperatures for materials and equipment to ensure that the plastic products created are appropriately formed and cured to quality standards.
    • Healthcare Applications: When peoples’ lives are on the line, accuracy is paramount. This is why temperature controllers are used across the healthcare industry in a range of applications. The pharmaceutical industry uses temperature controllers to ensure that chemical ingredients are kept within specific ranges. Laboratories use temperature controllers to ensure that samples are held at consistent temperatures to prevent degradation. Autoclaves, incubators, refrigerators and crystallization growing chambers also rely on temperature controllers.


  • Food and Beverage Applications: Temperature control is also essential in the food and beverage industry. Cooking ovens and food packaging machinery rely on temperature control as do many other aspects of the industry. For example, brewing, blending and sterilization processes require careful temperature monitoring and control to ensure that the food produced meets FDA requirements. Controllers help ensure that all food products resulting from these processes meet federal standards.

If your company uses any one of these applications, your operations likely rely on a temperature control system. With so much on the line, it’s essential to make sure that your temperature controller is operating as intended and is maintained appropriately. This is where Global Electronic Services can help.

Call Global Electronic Services for Temperature Controller Repair

A failing temperature controller can mean significant costs and losses for your company. Keep your operations running smoothly with a qualified temperature controller repair service that can offer high-quality, cost-effective results.

Global Electronic Services is a repair company that specializes in industrial electronics. We’ve worked with more than 60,000 of the world’s largest and most advanced manufacturers and distributors, and we’ve repaired and serviced everything from temperature controllers and electric motors to hydraulics and pneumatics and their related electronics.

When you choose Global, you’ll work with a company that is dedicated to quality customer service. Our team is always 14/7 to help our clients with any questions they may have. We also promise quick service with a standard repair time of one to five days and a two-day rush service to help keep your downtime to a minimum. We’re so confident in the abilities of our factory-trained and certified technicians that we even offer an 18-month in-service warranty for all the parts that we repair.

If cost is a concern for you, we’ve got you covered. We offer some of the most cost-efficient services in the industry and offer a 10 percent price guarantee. We also provide excellent pre-service evaluations and quotes and will discuss your options with you to ensure that you understand the cost of the repairs before we get started.

If you’re interested in our temperature controller repair services, contact us today by phone or use our easy online form to request a quote.

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