Smart Positioners

Smart Positioners are digital valve controllers based on microprocessor with internal logic capabilities and advance diagnostics features. These smart positioners have capabilities of automatic configuration & calibration. These valve positioners perform faster diagnostics which can be carried out through DCS, PC Software tool, Handheld & remote communicator. A diagnostics data may include installation, calibration leak detection, performance parameters data, history data etc. Built-in micro-processor optimizes the positioner performance and provides unique functions such as Auto-Calibration, PID Control, and HART Protocol Communications. Typical Smart positioners (from Emerson DVC & From YTC 3300 Manual) are showing below-

Electronic valve positioners achieve superior position control when compared to mechanical valve positioners, but their array of sensors and digital communication ability provides a new level of diagnostic data both to maintenance personnel and the supervising control system (if programmed to monitor and act on this data). Examples of diagnostic data provided by electronic positioners include:

  • Supply air pressure
  • Actuator air pressure
  • Ambient temperature
  • Position and pressure errors
  • Total valve stem travel (like an odometer in an automobile)

An Inside view of Emerson DVC 6200 & DVC2000 is shown below-


Additionally, the microprocessor embedded within an electronic valve positioner is capable of performing self-tests, self-calibrations, and other routine procedures traditionally performed by instrument technicians on mechanical valve positioners. Smart positioners can also access to such measurements as total valve stem travel even allows an electronic positioner to predictively calculate packing wear-out time, automatically flagging a maintenance alarm notifying operators and/or instrument technicians when the valve’s stem packing will need to be replaced. A useful capability of some “smart” valve positioners – since they monitor actuator air pressure in addition to stem position – is the ability to maintain a respectable degree of valve control in the event of a stem position sensor failure.

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Control Valves Accessories

Actuators

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