What Are the Different Types of Digital / Temperature Controllers?

There are three basic types of controllers: on-off, proportional and PID. Depending upon the system to be controlled, the operator will be able to use one type or another to control the process.

On/Off Control

An on-off controller is the simplest form of temperature control device. The output from the device is either on or off, with no middle state. An on-off controller will switch the output only when the temperature crosses the setpoint. For heating control, the output is on when the temperature is below the setpoint, and off above setpoint. Since the temperature crosses the setpoint to change the output state, the process temperature will be cycling continually, going from below setpoint to above, and back below. In cases where this cycling occurs rapidly, and to prevent damage to contactors and valves, an on-off differential, or “hysteresis,” is added to the controller operations. This differential requires that the temperature exceed setpoint by a certain amount before the output will turn off or on again. On-off differential prevents the output from “chattering” or making fast, continual switches if the cycling above and below the setpoint occurs very rapidly. On-off control is usually used where a precise control is not necessary, in systems which cannot handle having the energy turned on and off frequently, where the mass of the system is so great that temperatures change extremely slowly, or for a temperature alarm. One special type of on-off control used for alarm is a limit controller. This controller uses a latching relay, which must be manually reset, and is used to shut down a process when a certain temperature is reached.

Proportional Control

Proportional controls are designed to eliminate the cycling associated with on-off control. A proportional controller decreases the average power supplied to the heater as the temperature approaches setpoint. This has the effect of slowing down the heater so that it will not overshoot the setpoint, but will approach the setpoint and maintain a stable temperature. This proportioning action can be accomplished by turning the output on and off for short time intervals. This “time proportioning” varies the ratio of “on” time to “off” time to control the temperature. The proportioning action occurs within a “proportional band” around the setpoint temperature. Outside this band, the controller functions as an on-off unit, with the output either fully on (below the band) or fully off (above the band). However, within the band, the output is turned on and off in the ratio of the measurement difference from the setpoint. At the setpoint (the midpoint of the proportional band), the output on:off ratio is 1:1; that is, the on-time and off-time are equal. if the temperature is further from the setpoint, the on- and off-times vary in proportion to the temperature difference. If the temperature is below setpoint, the output will be on longer; if the temperature is too high, the output will be off longer.

PID Control

The third controller type provides proportional with integral and derivative control, or PID. This controller combines proportional control with two additional adjustments, which helps the unit automatically compensate for changes in the system. These adjustments, integral and derivative, are expressed in time-based units; they are also referred to by their reciprocals, RESET and RATE, respectively. The proportional, integral and derivative terms must be individually adjusted or “tuned” to a particular system using trial and error. It provides the most accurate and stable control of the three controller types, and is best used in systems which have a relatively small mass, those which react quickly to changes in the energy added to the process. It is recommended in systems where the load changes often and the controller is expected to compensate automatically due to frequent changes in setpoint, the amount of energy available, or the mass to be controlled.

Shimaden Digital / Temperature Controller – Distributor in Malaysia, Indonesia, Singapore and Philippines.

Temperature controller is an instrument used to control temperatures, mainly without extensive operator involvement. A controller in a temperature control system will accept a temperature sensor such as a thermocouple or RTD as input and compare the actual temperature to the desired control temperature, or setpoint. It will then provide an output to a control element.

A good example would be an application where the controller takes an input from a temperature sensor and has an output that is connected to a control element such as a heater or fan. The controller is usually just one part of a temperature control system, and the whole system should be analyzed and considered in selecting the proper controller.

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Dpstar supplies temperature controllers ranging from standard off-the-shelf models to custom temperature control configurations that incorporate time, temperature, motion, speed, pressure, and humidity for OEM applications. We are your “one stop shop” for measurement and temperature control of your critical process applications. If you manufacture process equipment for packaging, foodservice, medical, image processing, hot melt equipment, or lab applications, let us assist you with the full temperature control solution you need.

Largest manufacturer of thermocouples (temperature sensors) and industrial heaters based in Malaysia

dpstar Group is the largest manufacturer of thermocouples (temperature sensors) and industrial heaters based in Malaysia. Our 25 years of expertise lies in complete factory/building automation and control components as well as process/hybrid control systems from project design up to testing, system integration, and commissioning. We have successfully built a strong reputation for electrical, instrumentation, and control systems and as a result expanded our foothold in Kuala Lumpur (KL), Petaling Jaya, Penang, Johor Bahru, Ipoh, Seremban, Melacca, Selangor, Kedah, Sabah, Sarawak through direct companies and ventured overseas in Asia through our partner companies in Thailand, Philippines, Singapore, Indonesia, and so on.

Why Choose dpstar

Your success depends on your supply chain partners. You need to know each one is an expert in their field and a company dedicated to being your long-term partner in success. That’s dpstar Group.

Let’s be honest. You don’t want to think twice about the ability and dependability of your critical suppliers. dpstar have over 25 years of expertise in the thermal control business, with our combined enginee ring knowledge measured in centuries. A “can-do” culture that takes on tough application challenges and providing solutions that produce positive results.

Give us the opportunity to demonstrate our extensive expertise. We’re certain you’ll agree, dpstar is the clear choice to be your thermal solutions partner.

Please visit us at www.dpstar.com.my or email to sbtoh@dpstar.com.my.

Heater Industries We Serve in Malaysia, Singapore, Indonesia, Philippines, Thailand and Vietnam.

dpstar Manufacturer is a highly recognized manufacturer and supplier of industrial heaters for a variety of industries worldwide. From cast heaters for plastics extruders to the most advanced contact thermal heaters used in the production of semiconductors. dpstar offers a comprehensive array of industrial heater products, both industry standard and custom designs, to suit virtually any thermal processing equipment.

Wherever there’s a need for heat and temperature control, dpstar has experience.

With the broadest product line in the industry, dpstar provides more heat and control systems for process heating applications than anyone in the world. We provide solutions for industries as diverse as transportation, pharmaceuticals, chemical processing, rubber, plastics, refrigeration, defrost, mining and metals.

Please visit us at www.dpstar.com.my or email to sbtoh@dpstar.com.my.

 

Welcome to dpstar Group

dpstar Group has positioned itself as a leader in the design and manufacture of high quality electric industrial heaters, temperature sensors, temperature controls and process systems.

Over the  25years, we have grown to meet each new challenge in the market through innovative product development, continuous process improvements, and a commitment to high quality standards.

Our design and manufacturing capabilities are diverse and flexible to satisfy all of your requirements. Also, our engineering experience supports you with product solutions from concept through production, and state-of-the-art design software allows our staff to provide dynamic visual enhancements of prototype designs prior to manufacturing.

And through it all, our mission remains total customer satisfaction through effective customer communication, on-time deliveries, defect-free products, and a total quality system that promotes constant improvement of our services and operations.

Give us the opportunity to demonstrate our deep expertise in thermal process developed from years of application design and support.

For more information, please visit us at www.dpstar.com.my or email to sbtoh@dpstar.com.my