the T48 Controller accepts signals from a variety of temperature sensors thermocouple or RTD elements), precisely displays the process temperature, and provides an accurate output control signal (time proportional or linear DC) to maintain the process at the desired temperature. the controller's comprehensive yet simple programming allows it to meet a wide variety of application requirements. the controller operates in the PID control mode for both heating and cooling, with on-demand auto-tune, which will establish the tuning constants. the PID tuning constants may be fine-tuned by the operator at any time and then locked out from further modification. the controller employs a unique overshoot suppression feature, which allows the quickest response without excessive overshoot. the unit can be transferred to operate in the manual mode, providing the operator with direct control of the output. the controller may also be programmed to operate in the ON/OFF control mode with adjustable hysteresis. A second setpoint is available on select models to allow quick selection of a different setpoint setting. dual 4-digit displays allow viewing of the process temperature and setpoint simultaneously. front panel indicators inform the operator of the controller and output status. On many models the main control output and the alarm outputs are field replaceable.