The GEMU 1231 electrical position indicator is suitable for linear valves with actuator strokes up to 20 mm (actuating travel). It has a corrosion resistant plastic housing and one or two inductive proximity switches acc. to NAMUR EN 50227. Switching rod and actuating spindle have a positive connection without axial play.
The electrical connection is via cable gland.

  • ATEX-marking:
    II 2G EEx ia IIC/IIB T6
    II 2D T 80°C IP 65
    -20°C Ta +60°C
  • Both proximity switches can be continuously and precisely adjusted, independently of each other, via threaded spindles
  • Device can be rotated through 360°
  • Customer-specified connectors available as an option
  • Simple mounting and retrofitting to GEMU linear actuators
  • Mounting to other valve makes possible
  • Compact design in a stable housing
  • The switches are not subject to wear, contactless detection
  • Protection class IP 65 to EN 60529


Type 1231
Field Bus Without Field Bus
Accessory Accessory
Switch 2-wire Namur
Electrical Connection M 16 cable gland
Connection Terminal block
Max. Switching Frequency 1.0 kHz
Inductive Proximity Switch P+F NJ 1,5-6, 5-15N or equivalent

Operating Conditions

Setting Range of Limit Switch 2-20 mm continuous
Ambient Temperature -20 to +60 ºC
Protection Class to EN 60529 IP 65
Operating Conditions Intended for use with process valves whose opening/closing speed does not exceed 1 meter/second. Metallically isolated components have to be connected to the potential equalisation via charge eliminators by the user (see directive 1999/92/EC (ATEX 137) and national provisions).


Switch Rated Voltage 8 V Namur
Switch Rated Current, Undamped ≥ 3 mA
Switch Rated Current, Damped < 1 mA


Housing Cover Polysulfone (PSU)
Housing Base Polypropylene 30% GF (PP)
Guide Piece 1.4305
Operating Spindle 1.4104
Damping Piece 1.4104

Electrical Connection

M 16 Cable Gland 1 x available
Cable Diameter 4.5 to 7 mm
Recommended Cross Section of Wire 0.75 mm²
Potential Equalisation stranded wire, yellow/green H 07 V-K 4.0

Note on Index X

N/A Operation in potentially explosive atmospheres only in conjunction with an ATEX complying isolator amplifier that is designed for the operation of NAMUR proximity switches, mechanical contacts or optocouplers and for which separate operating instructions apply.