Watlow Electric Ramping and Profiling Microprocessor-Based Control SERIES 1500 - Manual (Page 88)

Restart:
RTD:
Set
point:
Signal conditioner:
Single .mode
cont rol :
Span:
Switching
sensltlvlty:
Thermal system:
Thermocouple:
Thermocouple
break protection:
Three mode control:
Time-In-step:
Time Proportioning
Control:
Trlac: Solid state switching device.
Two posltlon
control: An ON/OFF control.
Warm Start: Start-up condition
where
all program information is remembered by the
instrument’s memory back-up protection. In the Series 1500, powering up
with
Dip Switch #6 in the OFF position gives a “Warm Start.”
Wet Bulb:
Zero switching:
To begin to control a thermal system again, after stopping control and holding
the process variable at a fixed value. A “restart” may occur with newly-
programmed information in microprocessor-based controls.
Resistance Temperature Detector. Resistive sensing device displaying linear
resistance versus temperature characteristics. Displays positive temperature
coefficient.
Intended value of the process variable.
An electronic circuit that provides sensor compatibility of the input signal for use
in the control. Includes linearization and/or sensor excitiation.
Proportioning control.
Distance in degrees or other units between the minimum and maximum
operating limits of a sensor or controller.
See "Hysteresis."
A regulated environment consisting of a heat source, heat transfer medium,
sensing device and a process variable control instrument.
Temperature sensing device that is constructed of two dissimilar metals
wherein a measurable, predictable voltage is generated corresponding to
temperature.
Fail-safe operation that assures output shutdown upon an open thermocouple
condition.
Proportioning control with auto-reset and rate.
Time remaining in any given program step.
Action which varies the amount of ON and OFF time when “close” to the set
point, i.e., in the proportional band. This variance is the result of the control
algorithm. In other words, the amount of time the output relay is energized
depends on the system control requirement.
Half of a wet bulb/dry bulb
%RH
sensor system, i.e., an RTD with a wet sock.
Action which provides output switching only at the zero voltage
crossing points
of the AC line.
88 WATLOW Series 1500 User's Manual
Glossary, Appendix