Temperature controller is a device that is used to measure and control temperature by accepting temperature sensors such as thermocouple or RTD as input and comparing measured temperature with desired control temperature. The output is provided to control element such as heater or fan without extensive involvement of operator. Temperature controllers are widely used in steam application such as to control product temperature, monitor steam flashing from boiling tanks as they are robust, reliable, easily installable, and tolerant of imperfect steam conditions.