Positioners are part of a control loop.

The loop consists of;

  • An instrument
  • A Controller
  • A Positioner
  • An actuated Valve

The Instrument measures the process and provides an output proportional to the process on a scale e.g. 4-20mA (which is most common)

The Controller receives the Instrument signal and compares it to the set-point (desired signal), then sends a derivative signal to the Positioner. This signal commands the Positioner to move the Actuated Valve in the direction which will drive the process to the set-point position.

The Actuated Valve responds to the signal from the Positioner and moves.

The Instrument measures the process and confirms that the set-point position has been reached.

Positioners generally use 3-15psi, 0-10 Ohm or 4-20mA control signals with 4-20mA becoming the global standard.

Positioners which provide diagnostic feedback to the control room of Valve response and condition are termed SMART Positioners.

Our range of Positioners includes the following:


  • Safe Area 3-15 psi and 4-20 mA versions
  • Intrinsically Safe
  • Explosion Proof
  • Stainless steel
  • Integral limit switches for feedback
  • Integral 4-20mA transmitters
  • HART capable devices
  • On-board diagnostics
  • High temperature versions
  • Low temperature versions to -40C
  • Fieldbus options including Profibus and FF
  • Partial stroke facility local and remote
  • Gauge blocks
  • Volume booster


  • ATEX
  • CSA/UL
  • GOST-R and RTN

Additional Services

  • Mounting kit design using CAD for linear and rotary actuator designs