Microcontrollers and Programmed Thermostats in Temperature Control Systems
Compared to a common thermostat, a timed thermostat used in temperature control systems is much more efficient and economical as a result of reduced energy costs. A common thermostat is manual, you have to manually turn an air conditioner on and off and also the heater. For a programmed thermostat it has memory chips and is computerized and automatically maintains the temperature of a room. It can be programmed to have different set point temperatures for different times, ie different temperatures for morning, afternoon and weekends, and adjusts automatically. A temperature control system is connected to a heating and cooling system and uses linear, logic, on-off, and other control systems.
On-off control systems are the cheapest and easiest to apply. They have a programmed thermostat and when the temperature rises above the set point, the air conditioner automatically turns on. When the temperature subsequently drops below the set point, the air conditioner turns off and the heater turns on. They are less expensive to operate but have wear and tear costs for temperature control valves. In linear control systems, the set point is regulated by a control loop made up of control algorithms (PID variables), sensors and actuators. The set point is adjusted by manipulating the measurement variable (MV) to reduce error and generate negative feedback. The control loop of the PID system makes use of feedback loops. These loops can be integrated by microcontrollers into a computer system. Open loop systems do not use feedback. Logic control systems are built with microcontrollers or programmable logic devices. They are easy to design but can handle complex systems. They are used to sequence mechanical operations in elevators, washing machines, and other systems.
Watlow Company is involved in the development of temperature control systems especially for plastic manufacturers. For industries whose operation requires highly engineered resins and tight tolerances, Watlow’s MI band heaters provide exceptional heat transfer, high watt densities and long heater life. This belt saves $0.04 per kilowatt hour. Watlow also provides high watt density; high temperature barrel heaters, cable heaters, power controllers, hot runner nozzle heaters and cartridge heaters. Watlow’s temperature control systems also include temperature sensors. These thermocouple temperature sensors provide precise and accurate temperature measurements. They are J-type thermocouple sensors and are in high demand in the plastics industry. Watlow’s MI strip heaters have a high level of performance and durability. They are manufactured by implanting a nickel-chromium element into Watlow’s proprietary mineral insulation.
In a Vehicle there is a heating and air conditioning control system. It has a compressor clutch cycle to control temperatures inside the car, it also has automated temperature controls (ATC). When temperatures are below room temperature, the ATC sensor produces a control signal that turns off the compressor and places the system in heating mode. Finally, Ray Stucker, director of temperature control products at Tricools, once said that selecting the right temperature control systems can boast productivity and save energy and money. Take the time to make sure you select the best systems.