The temperature controller is a kind of intelligent temperature control instrument. It has the functions of temperature curve programmable or fixed-point constant temperature control, multiple PID regulation, output power limiting curve programming, manual / automatic switching, soft start, alarm switch output, real-time data query, communication with computer, etc. It combines digital temperature meter and ZK thyristor voltage regulator into one, which integrates temperature measurement, regulation and driving. The meter directly outputs thyristor trigger signal, which can drive all kinds of thyristor loads. It is used in all kinds of high and low voltage switchgear, dry-type transformer, box type substation and other related temperature application fields. In addition to understanding what the temperature controller is, we also need to know its three "how": how to work, how to use, and how to choose the temperature controller for better use of ATO.