Watlow Series 920 Microprocessor-Based Ramping Control - Manual (Page 74)

SYSTEM:
Switching
sensitivity:
Thermal
System:
Thermocouple:
Thermocouple break
protection:
Three mode
control:
TI
Time proportioning
control:
Triac: Solid state switching device.
WAITFOR: One of six step types under the PROGRAM menu of the Series
920 that can be programmed to wait for a specific amount of
time, or a process value.
Warm start:
WHR:
WMN:
WPV:
Zero switching:
One of three main level operating parameters. From the
SYSTEM menu, you can generate a non-ramping set point
(fixed), manipulate Events 1 and 2, clear error codes and
latching alarms.
In ON/OFF controls, the temperature change necessary to
change the output from full ON to full OFF (3°F or 1.7°C in the
Series 929).
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 dissimi-
lar metals wherein a measureable, predictable voltage is
generated corresponding to temperature.
Fail-safe operation that assures output shutdown upon an open
thermocouple condition.
Proportioning control with reset and rate.
Represents the Real Time hours and minutes of the Series
920's system.
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 proportional to the diierence between the set point
and the actual process temperature. In other words, the
amount of time the output relay is energized depends on the
system temperature.
Start-up condition where all program Information is remem-
bered by the instrument’s memory backup protection.
The hour that the system will wait for relative to when the step
began. This is not a measure of time-of-day.
Represents the minutes that the system will wait for relative to
when the step began. This is not a measure of time-ofday.
Temperature that the system will compare against the process
variable, and wait for, before proceeding to the next step.
Action which provides output switching only at the zero voltage
crossing points of the AC line.
74 WATLOW Series 920 User’s Manual