Emerson Fisher FIELDVUE DVC6000, Instruction Manual

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DVC6000 Digital Valve Controllers
September 2013 Glossary-2
Controller
A device that operates automatically to regulate a
controlled variable.
Crossover Point
The point at which the feedback pin is closest to
the axis of rotation of the travel sensor. A visual
indication of the crossover point is found when
the slot in the instrument feedback arm forms a
90-degree angle with the valve stem.
Current-to-Pressure (I/P) Converter
An electronic component or device that converts
a milliamp signal to a proportional pneumatic
pressure output signal.
Cycle Counter
The capability of a FIELDVUE instrument to
record the number of times the travel changes
direction. The change in direction must occur
after the deadband has been exceeded before it
can be counted as a cycle.
Cycle Counter Alert
Checks the difference between the Cycle Counter
and the Cycle Counter Alert Point. Cycle Counter
Alert is active when the cycle counter value
exceeds the Cycle Counter Alert Point. It clears
after you reset the Cycle Counter to a value less
than the alert point.
Cycle Counter Alert Point
An adjustable value which, when exceeded,
activates the Cycle Counter Alert. Valid entries
are 0 to 4 billion cycles.
Cycle Counter Deadband
Region around the travel reference point, in
percent of ranged travel, established at the last
increment of the Cycle Counter. The deadband
must be exceeded before a change in travel can
be counted as a cycle. Valid entries are 0% to
100%. Typical value is between 2% and 5%.
Deviation
Usually, the difference between set point and
process variable. More generally, any departure
from a desired or expected value or pattern.
Device ID
Unique identifier embedded in the instrument at
the factory.
Device Revision
Revision number of the interface software that
permits communication between the Field
Communicator and the instrument.
Drive Signal
The signal to the I/P converter from the printed
wiring board. It is the percentage of the total
microprocessor effort needed to drive the valve
fully open.
Drive Signal Alert
Checks the drive signal and calibrated travel. If
one of the following conditions exists for more
than 20 seconds, the Drive Signal Alert is active.
If none of the conditions exist, the alert is cleared.
If Zero Power Condition = Closed
The alert is active when:
drive signal <10% and calibrated travel >3%
drive signal >90% and calibrated travel <97%
If Zero Power Condition = Open
The alert is active when:
drive signal <10% and calibrated travel <97%
drive signal >90% and calibrated travel >3%
Equal Percentage
A valve flow characteristic where equal
increments of valve stem travel produce equal
percentage changes in existing flow. One of the
input characteristics available for a FIELDVUE
Instrument. See also, Linear and Quick Opening.
Feedback Arm
The mechanical connection between the valve
stem linkage and the FIELDVUE Instrument
travel sensor.
Feedback Connection
Identifies the type of feedback linkage: rotary,
sliding-stem roller or sliding-stem standard.
Feedback Signal
Indicates to the instrument the actual position of
the valve. The travel sensor provides the
feedback signal to the instrument printed wiring
board assembly. A mechanical linkage connects
the travel sensor to the valve stem or shaft.
B
Glossary