In extrusion operations, the temperature controls are controllers used for the individual zones in the barrel, die, and screen changer. They are placed in the control panel in a series based on how many zones or ancillary pieces of equipment you that are required. 

Oil Temperature Control Units

Oil controllers are used in high heat applications. They are used to preheat molds and keep them at a constant temperature by circulating the fluid through the molds.

Hot runner temperature controllers manage a series of zones in one location to regulate temperature in complex molds.