Watlow Series D8 - Manual (Page 215)

Series D8 User’s Guide Glossary
Doc. 0600-3120-2000 Watlow Anafaze 197
Glossary
A
AC
See Alternating Current.
AC Line Frequency
The frequency of the ac line power measured in Hertz
(Hz), usually 50 or 60 Hz.
Accuracy
Closeness between the value indicated by a measuring
instrument and a physical constant or kno wn stan-
dards.
Action
The response of an output when the process v ariable
is changed. See also Direct Action, Reverse Action.
Address
A numerical identifier for a controller when used i
computer communications.
Alarm
A signal that indicates that the process has e xceeded
or fallen below a certain range around the set point.
For example, an alarm may indicate that a process is
too hot or too cold. See also Failed Sensor Alarm,
Global Alarm, High De viation Alarm, High Alarm,
Loop Alarm, Low Deviation Alarm, Low Alarm.
Alarm Delay
The lag time before an alarm is activated.
Alternating Current (AC)
An electric current that re verses at re gular intervals,
and alternates positive and negative values.
Ambient Temperature
The temperature of the air or other medium that sur -
rounds 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.
Ammeter
An instrument that measures the magnitude of an
electric current.
Ampere (Amp, A)
A unit that defines the rate of f w of electricity (cur-
rent) in the circuit. Units are one coulomb (6.25 x
1018 electrons) per second.
Analog Output
A continuously v ariable signal that is used to repre-
sent a v alue, such as the process v alue or set point
value. Typical hardw are configurations are 0 t
20mA, 4 to 20mA or 0 to 5 Vdc.
Automatic Mode
A feature in which the controller sets PID control out-
puts in response to the process v ariable and the set
point.
Automatic Reset
The integral function of a PI or PID temperature con-
troller that adjusts the process temperature to the set
point after the system stabilizes. The inverse of inte-
gral.
Autotune
A feature that automatically sets temperature control
PID values to match a particular thermal system.
AWG
See American Wire Gauge.
B
Baud Rate
The rate of information transfer in serial communica-
tions, measured in bits per second.
BCD
Binary coded decimal. F or BCD job loading, the
binary states of three digital inputs are decoded as
decimal numbers 1 to 8.
Bumpless Transfer
A smooth transition from automatic (closed loop) to
manual (open loop) operation. The control output
does not change during the transfer.
C
Calibration
The comparison of a measuring de vice (an unknown)
against an equal or better standard.