Watlow PPC-2000 - Manual (Page 313)

Doc.# 30002-00 Rev 2.3 Watlow Anafaze 285
Glossary
A
Alarm
A signal that indicates that the process has
exceeded or fallen below a certain range around
the setpoint. For example, an alarm may indicate
that a process is too hot or too cold. See also:
Deviation Alarm
Failed Sensor Alarm
Global Alarm
High Deviation Alarm
High Process Alarm
Loop Alarm
Low Deviation Alarm
Low Process Alarm
Ambient Temperature
The temperature of the air or other medium that
surrounds the components of a thermal system.
American Wire Gauge (AWG)
A standard of the dimensional characteristics of
wire used to conduct electrical current or signals.
AWG is identical to the Brown and Sharpe
(B&S) wire gauge.
Analog input
A continuously variable signal that is generated
by a process sensor and measured by a controller.
It usually represents a value, such as process vari-
able. Some analog input signals are –10 to 100
mV, 4-20 mA, 0-5Vdc
Analog Output
A continuously variable signal that is generated
to control a process element, such as a heater or
motor speed. Some analog output signals are 0-
20 mA and 0-10Vdc.
Auto Mode
A feature that allows the controller to set PID
control outputs in response to the Process Vari-
able (PV) and the setpoint.
B
Baud Rate
The rate of information transfer in serial commu-
nications, measured in bits per second.
Boolean
A variable with a value of either 1 or 0.
C
Calibration
The comparison of a measuring device (an
unknown) against an equal or better standard.
Channel
The hardware and firmware that determine the
behavior of control and alarm outputs based on
user set parameters and measured feedback.
Closed Loop
A control system that uses a sensor to measure a
process variable and makes decisions based on
that feedback.
Control Action
The response of a control output when the pro-
cess variable is changed.
Control Loop
A system that affects controlled elements (out-
puts) either in response to process or user defined
input.
Control Mode
The type of action that a controller uses. For
example, On/Off, time proportioning, PID, Auto-
matic or manual, and combinations of these.
Cool
A control method and association of parameters
organized around maintaining temperature below
ambient.
Current
The rate of flow of electricity. The unit of mea-
sure is the ampere (A).
1 ampere = 1 coulomb per second.