In addition to inputs, every controller also has an output. This feature enables the controller to stop the process immediately if a sensor break condition is detected. Undetected, this fault condition could cause significant damage to the equipment being controlled. Controllers can also accept milliamp signals such as 0 to 20mA or 4 to 20mA.Ī controller will typically incorporate a feature to detect when an input sensor is faulty or absent. Controllers may also be set up to accept millivolt signals from sensors that include 0 to 50mVDC and 10 to 50mVDC. Typical input voltage signals include 0 to 5VDC, 1 to 5VDC, 0 to 10VDC and 2 to 10VDC. A typical RTD would be a 100Ω platinum sensor.Īlternatively, controllers can be set to accept voltage or current signals in the millivolt, volt, or milliamp range from other types of sensors such as pressure, level, or flow sensors. Typical standardized thermocouple types include J, K, T, R, S, B and L types among others.Ĭontrollers can also be set to accept an RTD as a temperature sensing input. Typical input sensors include thermocouples and resistive thermal devices (RTD's), and linear inputs such as mV and mA. The type of input sensor and signal needed may vary depending on the type of controlled process. Temperature controllers can have several types of inputs. In the case of a temperature controller, the measured variable is temperature. The inputs are used to measure a variable in the process being controlled. Controllers regulate temperature and/or process time to ensure optimum performance.Īll controllers have several common parts. Common equipment using temperature controllers includes laboratory and test equipment, autoclaves, incubators, refrigeration equipment, and crystallization growing chambers and test chambers where specimens must be kept or tests must be run within specific temperature parameters.Ĭommon food processing applications involving temperature controllers include brewing, blending, sterilization, and cooking and baking ovens. Temperature controllers are used in the healthcare industry to increase the accuracy of temperature control. In extruding equipment, temperature controllers are used to precisely monitor and control temperatures at different critical points in the production of plastic.
#Pc recorder controller input portable#
Temperature control in the plastics industry is common on portable chillers, hoppers and dryers and molding and extruding equipment. Temperature controllers precisely regulate these operations to ensure a high quality product output. In the packaging world, machinery equipped with seal bars, glue applicators, hot melt functions, shrink wrap tunnels or label applicators must operate at designated temperatures and process time lengths. Temperature controllers are used in ovens and in heat-treating applications within furnaces, ceramic kilns, boilers, and heat exchangers. The following is a brief overview of some common temperature control applications in industry: Some common uses for temperature controllers in industry include plastic extrusion and injection molding machines, thermo-forming machines, packaging machines, food processing, food storage, and blood banks. Temperature controllers are used in a wide variety of industries to manage manufacturing processes or operations.
When the actual temperature deviates from the setpoint, the controller generates an output signal to activate other temperature regulating devices such as heating elements or refrigeration components to bring the temperature back to the setpoint. This sensed temperature is constantly compared to a user setpoint. In a typical application, sensors measure the actual temperature. A basic temperature controller provides control of industrial or laboratory heating and cooling processes. Temperature controllers in industry work much the same way they do in common household applications.
So if the temperature gets too high, a controller initiates an action to bring the temperature down. Thermostats are also used in refrigerators.
If it falls below the set temperature, it sends a signal to activate the heater to raise the temperature back to the setpoint. When a temperature is set for an oven, a controller monitors the actual temperature inside of the oven.
Temperature controllers are also used in ovens. For instance, a hot water heater uses a thermostat to control the temperature of the water and maintain it at a certain commanded temperature. The simplest example of a temperature controller is a common thermostat found in homes. Closed loop control block diagram Introduction to Temperature ControllersĪ temperature controller is a device used to hold a desired temperature at a specified value.
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