Heater controllers and temperature controllers, also known as process controllers, provide control to a variety of heaters, coils and perfusion heating devices without extensive operator involvement.

There are different types of temperature controllers available in the market, such as on-off controllers, proportional controllers, PID controllers and multi-loop PID controllers. The type of input sensor, the type of output and number of outputs, and the method of control should be considered when choosing a controller to integrate into a control system.

Some controllers use:

• A simple on/off switch for predetermined temperature levels
• Proportional control, which provides some level of feedback
• Proportional-integral-derivative (PID) units with a complete feedback loop that assesses a number of process variables for more accurate temperature control

Heater controllers may be designated for a single type of heater or may be multipurpose. They may accommodate more than one heating device, with two or more separate and independent circuits. Some controllers have thermostats and can operate as a back-up to other heating processes. Controllers may be equipped with timers or alarms, and some can accept various temperature probes as input.