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

GE Oil and Gas
SVI II AP Instruction Manual
Physical and Operational Description
Electronics Module
The SVI II AP is housed in an industrial, tough, weatherproof, corrosion resistant
aluminum housing that has been designed for operation in hazardous areas as listed in
Appendix B. Electrical connections are made through two 1/2" NPT conduit entries.
Pneumatic connections are made through two or three ¼" NPT ports.
The Electronics module consists of an electronic circuit encapsulated in a housing. The
electronics include a multiplexer, A/D, D/A, temperature sensor, Hall-Effect magnetic
position sensor, pressure sensors, a micro controller, and a power management/
distribution circuit. The programs controlling the SVI II AP digital valve positioner are
stored in a flash memory that allows for the downloading of upgraded firmware.
A separate non-volatile memory stores configuration information, and continuous
diagnostic results. Expansion capabilities include connectors for the addition of the
optional local display with pushbuttons. Using the internal programmed positioner
algorithm, the CPU computes the required output based on information received from the
measurement sensors. The base module has no user repairable components.
Magnetic Position Sensor
Position Retransmit
Pressure Sensor
A non-contact sensor uses a magnetic field to transfer the position through the wall of the
housing, without penetration, to sense the valve position. A Hall effect device, sealed
within the electronics housing, senses the rotation of a magnetic assembly mounted on
the end of a rotary valve shaft or on a driven linkage mounted on a reciprocating valve.
The output of the Hall sensor provides the position feedback signal to the position control
algorithm. The magnetic assembly is environmentally sealed and is entirely external to
the electronics housing (See Figure 11 on page 37). The Hall effect sensor has a
maximum travel range of up to 140° rotation.
The position sensor also provides, through the electronics module, readout of valve
position on the optional display and communication of valve position via HART protocol.
The position transmission option provides a 4 - 20 mA signal proportional to valve
position transmitted on a separate pair of leads. A pair of contacts can signal high and low
position limits.
The pressure sensor located in the Electronics Module measures the output of the single
acting relay. The pressure measurement is displayed on the local display or read by a
HART communication device.
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