Masoneilan SVI II AP Installation and Maintenance ... - GE Energy

Padj (%)
Position
Compensation
Damping Coefficient
Dead Zone(%)
Quick Opening
Relay, Pneumatic
Safe Area
Sig Hi
Sig Lo
Single Acting
Split Range
STOPS
Valves often have significantly different response when filling
versus exhausting. The proportional gain is adjusted by adding
Padj to P when the valve is exhausting. Padj is normally less
than P.
The response of the valve is different when the valve is nearly
closed Coefficient than when the valve is nearly open. The position
compensation coefficient, which is a number between 0
and 9, allow the control algorithm to optimize the valve
response.
The valve response can be made slower for some applications.
A value of 0 gives no damping, and a value of 9 gives maximum
damping of valve motion.
When the valve position is within the setpoint +⁄- the dead zone,
no additional position control is performed. This value is normally
0%, however for high friction valves (e.g. valves with
graphite packing) a higher dead zone helps avoid limit cycling
due to the stick⁄slip action of the valve. In these cases the dead
zone chosen might be 0.2% to 1%.
(see Characteristic)
The component that amplifies the pneumatic control signals to
provide a wide range of actuation pressure and to supply and
vent at high flow rates for responsive control.
The area of a plant where there never is an explosion hazard
present, such as the control room or a wire marshalling rack
area.
In the SVI II AP configuration, the input current setting at which
the valve is fully open (ATO) or fully closed (ATC).
In the SVI II AP configuration, the input current setting at which
the valve is fully closed (ATO) or fully open (ATC).
The action of a position with a single pneumatic output for operation
with a spring return actuator. (see double acting).
A control configuration where a single control output is sent to
two or more control valves. Each control valve positioner is calibrated
to respond to a separate portion of the control signal. An
example is a steam valve and a cooling water valve arranged to
be both closed at 50% and the steam valve to open.
The SVI II AP runs STOPS procedure to adjust the positioner to
actual valve travel. First the output pressure is reduced to zero
and the position is recorded. That position corresponds to 0%.
The output pressure is raised to its maximum based on supply
pressure. The position is recorded and corresponds to 100%.
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