Series 285 Rotary Smart Positioner

Brand: Dwyer Instruments, LLC

Proximity Series 285 Smart Positioners combine an easy to use, high performance unit with a low price.

Series 285 models accurately control the valve stroke of rotary motion valves, such as W.E. Anderson ball or butterfly valves, according to an input signal of 4 to 20 mA from the controller. Its rugged, durable design makes it ideal for harsh environments.

The NEMA 4X (IP66) enclosure rating protects the highly efficient microprocessing unit inside the Smart Positioner. An Analog feedback signal is outputted to stabilize any valve system, and easy to use functions such as auto calibration ensure the accuracy of the unit.

Low air consumption reduces operating cost but does not sacrifice the performance of the Smart Positioner.

The compact design of this unit makes it easy to use with any size actuator. Smart Positioners feature a LCD screen attached to the outer surface of the unit, allowing for an easy inspection of the positioner condition while in the field.

Available in user selectable single or double action, with HART® communication as standard. In the event that the 4-20 mA input signal is lost the 285 will fail in place.
  • User selectable single or double action
  • LCD display


Air Consumption

  • 0.0004 to 2.1 scfm (0.01 to 60 LPM) at psig: 20 (kPa: 138, bar: 1.38) - Flow Capacity

Conduit Connection

  • 1/2” NPT

Enclosure, Body Material

  • 316 Stainless Steel
  • Aluminum

Environmental Protection

  • IP66
  • NEMA 4X


  • ± 0.05 % of Span

Input Impedance

  • 460 ohms, Max.

Input Signal

  • 0 to 90° - Stroke
  • 4-20 mA DC


  • ≤ ± 0.5 % of Full Scale

NPT Connection

  • 1/4” NPT Female - Air Connection
  • 1/8” NPT Female - Gage Connection


  • ± 0.3 % of Full Scale


  • ± 0.2 % of Full Scale

Supply Pressure

  • psi: 35 to 116 (kPa: 240 to 900, bar: 2.4 to 9) - Air Supply

Temperature Range

  • -30° to 85° C (-22° to 185° F)

  • Linear motion valves or rotary motion valves with single or double acting actuators
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