User`s guide
Glossary
78 ANASOFT User’s Guide
F
Fahrenheit
The temperature scale that sets the freezing point
of water at 32
º
F and its boiling point at 212
º
F at
standard atmospheric pressure. The formula for
conversion to Celsius is:
º
C=5/9 (
º
F-32
º
F).
Failed Sensor Alarm
Warns that an input sensor no longer produces a
valid signal. For example, when there are thermo-
couple breaks, infrared problems or resistance
temperature detector (RTD) open or short fail-
ures.
Filter
Filters are used to handle various electrical noise
problems.
Di
g
ital Filter
(DF)
—
A filter that allows the
response of a system when inputs change unreal-
istically or too fast. Equivalent to a standard
resistor-capacitor (RC) filter
Di
g
ital Ada
p
tive Filter
—
A filter that rejects
high frequency input signal noise (noise spikes).
Heat/Cool Out
p
ut Filter
—
A filter that slows
the change in the response of the heat or cool out-
put. The output responds to a step change by
going to approximately 2/3 its final value within
the numbers of scans that are set.
Fre
q
uenc
y
The number of cycles over a specified period of
time, usually measured in cycles per second. Also
referred to as Hertz (Hz). The reciprocal is called
the period.
G
Gain
The amount of amplification used in an electrical
circuit. Gain can also refer to the Proportional (P)
mode of PID.
Global Alarm
Alarm associated with a global digital output that
is cleared directly from a controller or through a
user interface.
Global Di
g
ital Out
p
uts
A pre-selected digital output for each specific
alarm that alerts the operator to shut down critical
processes when an alarm condition occurs.
Ground
An electrical line with the same electrical poten-
tial as the surrounding earth. Electrical systems
are usually grounded to protect people and equip-
ment from shocks due to malfunctions. Also
referred to a "safety ground".
H
Hertz(Hz)
Frequency, measured in cycles per second.
Hi
g
h Deviation Alarm
Warns that the process is above setpoint, but
below the high process variable. It can be used as
either an alarm or control function.
Hi
g
h Power
(As defined by ANAFAZE) Any voltage above
24 VAC or Vdc and any current level above 50
mAac or mAdc.
Hi
g
h Process Alarm
A signal that is tied to a set maximum value that
can be used as either an alarm or control function.
Hi
g
h Process Variable (PV)
See Process Variable (PV).
Hi
g
h Readin
g
An input level that corresponds to the high pro-
cess value. For linear inputs, the high reading is a
percentage of the full scale input range. For pulse
inputs, the high reading is expressed in cycles per
second (Hz).