A heater system is provided. The system includes a resistive element with a temperature coefficient of resistance (TCR) of at least about 1,000 ppm such that the resistive element functions as a heater and as a temperature sensor and the resistive element is a material having greater than about 95% nickel. The system also includes a heater control module including a two-wire controller with a power control module that is configured to periodically compare a measured resistance value of the resistive element against a reference temperature to adjust for resistance drift over time during operation such that a temperature drift of the resistive element is less than about 1% over a temperature range of about 500° C.-1,000° C.