Emerson Fisher FIELDVUE DVC2000 Instruction Manual page 96

DVC2000 Digital Valve Controller
Travel Cutoff
Defines the cutoff point for the travel, in percent
of ranged travel. There are two travel cutoffs:
high and low. Once travel exceeds the cutoff, the
drive signal is set to either maximum or minimum,
depending on the Zero Control Signal and if the
cutoff is high or low. Minimum opening time or
minimum closing time are not in effect while the
travel is beyond the cutoff. Use the travel cutoff to
obtain the desired seat load or to be sure the
valve is fully open.
Travel Deviation
The difference between the analog input signal (in
percent of ranged input), the "target" travel, and
the actual "ranged" travel.
Travel Deviation Alert
Checks the difference between the target and the
ranged travel. If the difference exceeds the Travel
Deviation Alert Point for more than the Travel
Deviation Time, the Travel Deviation Alert is
active. It remains active until the difference is less
than the Travel Deviation Alert Point.
Travel Deviation Alert Point
An adjustable value for the target travel and the
ranged travel difference, expressed in percent,
When this value is exceeded by the travel
deviation for more than the Travel Deviation
Time, the Travel Deviation Alert is active. Valid
entries are 0% to 100%. Typically this is set to
5%.
Travel Deviation Time
The time, in seconds. that the travel deviation
must exceed the Travel Deviation Alert Point
Glossary
before the alert is active. Valid entries are 1 to 60
seconds.
Glossary-6
Travel Limit
A setup parameter that defines the maximum
allowable travel (in percent of ranged travel) for
the valve. During operation, the travel target will
not exceed this limit. There are two travel limits:
high and low. Typically the travel limit low will be
used to keep the valve from going completely
closed.
Travel Range
Travel, in percent of calibrated travel, that
corresponds to the input range.
Travel Sensor
A device within the FIELDVUE instrument that
senses valve stem or shaft movement.
Tuning
The adjustment of control terms or parameter
values to produce a desired control effect.
Tuning Set
Preset values that identify gain settings for a
FIELDVUE instrument. The tuning set and supply
pressure together determine an instrument's
response to input signal changes.
Watch Dog Timer
A timer that the microprocessor must rearm
periodically. If the microprocessor is unable to
rearm the timer, the instrument goes through
reset.
Zero Control Signal
A setup parameter that determines whether the
valve is fully open or fully closed when the input
signal is 0%.
July 2009