12/22/14
8
Rev.5 (EC 02.293.435)
Auto-tune: Automatically tunes the parameters to fit the characteristics of your particular thermal system.
Cold junction compensation: Electronic means to compensate for the effect temperature at the cold junction.
Cycle time: The time necessary to complete a full On-through-Off period in a time proportioning control system.
Derivative/Rate: Anticipatory action that senses the rate of change of the process, and compensates to minimize
overshoot and undershoot.
Default parameters: The parameters (programmed instructions) permanently stored in microprocessor software to
provide the data base.
Droop: Difference in temperature between set point and stabilized process temperature.
Hysteresis: In On/Off control, the temperature change necessary to change the output from On to full Off.
Input (sensor): Process variable information being supplied to the instrument.
Integral/Reset: Control action that automatically eliminates offset, or "droop", between set point and actual process
temperature.
Offset: Adjustment to actual input temperature and to the temperature valves the control uses for display and control.
ON/OFF control: Control of temperature about a set point by turning the output full On below set point and full Off above
set point.
Output: Action in response to difference between set point and process variable.
Overshoot: Condition where temperature exceeds steeping due to initial power up or process changes.
Parameter: a physical property whose value determines the response of a electronic control to given inputs.
PID: Proportioning control with auto-reset and rate.
Process variable: Thermal system element to be regulated, such as time, temperature, relative humidity, etc.
Proportional band: Span of temperature about the set point where time proportional control action takes place.
Set point: Intended value of the process variable.
Thermal system: A regulated environment consisting of a heat source, heat transfer medium, sensing device and a
process variable control.
Thermocouple: Temperature sensing device that is constructed of two dissimilar metals wherein a measurable,
predicative voltage is generated corresponding to temperature.
Thermocouple break protection: Fail-safe operation that assures output shutdown upon an open thermocouple condition.
Time Proportioning Control: Action which varies the amount of ON and OFF time when "close" to the set point (within the
proportional band). This variance is proportional to the difference between the set point and the actual process
temperature.
Maintenance
Simple preventative maintenance steps include keeping the controller clean. Protect it from overload, excessive dirt, oil
and corrosion.
