Flowserve Logix MD+ ValveSight - Manual (Page 236)

ValveSight™ Diagnostics DTM Manual for Logix MD+ Positioner with HART®
FCD- LGENSF0014-00
© Flowserve Corporation
236
The positioner makes a correction by applying an adjustment to the input command
according to a characterization curve.
Linear - Select Linear if the actuator position should be directly proportional to the
command input signal. (For most rotary valves, this setting gives an =% Cv characteristic
due to their inherent =% characteristics.)
Other - Select Other if one of the pre-set characterization curves or a custom curve is
desired. The default will be the Custom curve which is populated with a standard 30:1
equal percent rangeability curve which generally opens less than the input command. To
select one of the other curve options, see the
Stroke Characterization page of the DTM.
Auto Tune Switch
Changing this from the DTM will have no effect.
This switch controls whether the positioner will automatically tune itself during the stroke
calibration (Quick-Cal), or use preset tuning parameters.
On - Selecting On enables an auto tune feature that will automatically determine the
positioner gain settings. The automatic tuning will be based on response parameters
measured during the latest Quick-Cal. The valve response is a combination of these
response parameters and the current position of the Selectable GAIN Switch.
Off - Selecting Off forces the positioner to use one of the factory preset tuning sets
determined by the Selectable GAIN Switch. Settings “B” through “J” are progressively
higher predefined tuning sets.
Selecting “A” on the Selectable Gain Switch during a Quick-Cal allows you to use and
preserve manually adjusted gains.
Quick Calibration Switch
Changing this from the DTM will have no effect.
This switch selects between Auto and Jog calibration modes.
Auto - Use the Auto setting if the fully opened position of the valve has a mechanical stop.
This is typical for most valves. In Auto mode during a stroke calibration (Quick-Cal), the
positioner will fully close the valve and register the 0% position, then fully open the valve to
register the 100% position.
Jog - Use the Jog setting if the fully opened position of the valve has no hard stop, but
needs to be set manually. In Jog mode during a stroke calibration (Quick-Cal), the
positioner will fully close the valve and register the 0% position, then wait for you to move
the valve to the 100% open position using the
▲
Up and
▼
Down buttons. Press the
► ACCEPT/QUICK-CAL button to accept the 100% location.
Valve Stability Switch
This switch adjusts the position control algorithm of the positioner for use with low-friction
control valves or high-friction automated valves.
Lo Friction - Placing the switch to Lo Friction optimizes the response for low friction, high
performance control valves. This setting provides for optimum response times when used
with most low friction control valves.
Hi Friction - Placing the switch to the right optimizes the response for valves and actuators
with high friction levels. This setting slightly slows the response and will normally stop limit
cycling that can occur on high friction valves. See section 10.3.7 Configuration (Pressure