Emerson FIELDVUE DVC6200f Instruction Manual page 64

DVC6200f Digital Valve Controller
D Travel Integral Enable
Travel Integral Enable (TVL_INTEG_ENABLE [44.1])
is used to enable the integral setting to improve static
performance by correcting for error that exists
between the travel target and actual travel.
D Travel Integral Gain
Travel Integral Gain (SERVO_RESET [19]) (also
called reset) is the ratio of the change in output to the
change in input, based on the control action in which
the output is proportional to the time integral of the
input.
D Travel Integral Dead Zone
4
Travel Integral Dead Zone (TVL_INTEG_DEADZ
[44.4]) is a window around the Primary Setpoint in
which the integral action is disabled. The dead band is
configurable from 0 to 2%.
D Travel Integral Limit Hi
Travel Integral Limit Hi (TVL_INTEG_LIM_HI [44.2])
provides an upper limit to the integrator output. The
high limit is configurable from 0 to 100% of the I/P
drive signal.
D Travel Integral Limit Lo
The Travel Integral Limit Lo (TVL_INTEG_LIM_LO
[44.3]) provides a lower limit to the integrator output.
The low limit is configurable from −100 to 0% of the I/P
drive signal.
D Performance Tuner
During performance tuning the valve
may move, causing process fluid or
pressure to be released. To avoid
personal injury and property damage
caused by the release of process fluid
or pressure, isolate the valve from the
process and equalize pressure on
both sides of the valve or bleed off
the process fluid.
Performance Tuner is used to determine digital valve
controller tuning. It will move the valve slightly and
monitor the effects of small tuning changes until an
optimum control response is achieved. Because the
Performance Tuner can detect internal instabilities
before they become apparent in the travel response, it
can generally optimize tuning more effectively than
manual tuning.
52
WARNING
D Stabilize/Optimize
WARNING
During Stabilize/Optimize the valve
may move, causing process fluid or
pressure to be released. To avoid
personal injury and property damage
caused by the release of process fluid
or pressure, isolate the valve from the
process and equalize pressure on
both sides of the valve or bleed off
the process fluid.
If after completing initial setup and calibration the
valve cycles or overshoots, or is sluggish, you can
improve operation by running Stabilize/Optimize.
Stabilize/Optimize is included with the device
description (DD) firmware. Stabilize/Optimize is
accessible from the transducer block and permits
changing the transducer block set point a small
amount to see if the valve is unstable or unresponsive.
If valve response is unsatisfactory, the method permits
adjusting the digital valve controller tuning to improve
response.
If the valve is unstable, select Decrease Response to
stabilize valve operation. This selects the next lower
tuning set (e.g., F to E). If the valve response is
sluggish, select Increase Response to make the valve
more responsive. This selects the next higher tuning
set (e.g., F to G).
If after selecting Decrease Response or Increase
Response the valve travel overshoot is excessive,
Increase Damping or Decrease Damping can be used
to select a damping value not represented in a
predefined tuning set. Select Decrease Damping to
select a damping value that allows more overshoot.
Select Increase Damping to select a damping value
that will decrease the overshoot.
When valve operation is satisfactory, select Exit.
Before exiting, you are asked if you want to return the
transducer block mode to Auto. Select Yes to change
the transducer block mode to Auto. Select No to leave
the transducer block in its current mode.
November 2010