MK18 Series

Cylindrical magnetically operated Reed Sensors


MK18 sensors are magnetically operated Reed proximity switches in a cylindrical module, fitted with interconnect cable. The sensor should be mounted on a fixed surface with the actuating magnet, e.g. M3, on the moving surface.  The Reed Sensor and magnet must be fixed in a definite distance to each other.  Approximation resp. removal of the magnet determines the closing and opening of the Reed Switch.  The magnetic pull-in / drop-out sensitivity is divided into five AT ranges.  A choice of switches, termination options and cable lengths is offered.


Position- and limit switch, e.g. pneumatic or hydraulic actuator position indication and end travel limit switch

Door and window contacts for the security system applications

Level sensor, use with magnetic floats for water level detection e.g. coffee-makers, washing-machines, dish-washers


Tolerance +/- 0.10mm (0.004 inch)


The standard termination is a two-wire flat cable with a cross section of 2 x 0.14mm². The standard cable length is 500mm, other lengths can be supplied on request. The required length has to be stated on the part number. The cable end can be supplied with the following connection styles (please note after the length in the part number).

W Cable end cut, dismantled on 30 mm, cores stripped and tinned on 5 mm


Contact Data

Contact type 39 40 87
Contact form A/dry A/dry A/dry
Rated Power max. (W) 10 10 10
Switching voltage max. (VDC) 100 200 200
Switching current max. (A) 0.25 0.5 0.5
Carry current (A) 0.5 0.75 1.0
Contact resistance max. mOhm 300 150 150
Breakdown voltage (contact/contact) min. (VDC) 150 250 250
Operating time incl. bounce (ms) 0.4 0.5 0.35
Releasing time (ms) 0.1 0.1 0.1
Operating temperature (°C) -20/+70 -55/+125 -20/+130
Storing temperature (°C) -35/+70 -55/+125 -35/+130

Other switches by request.

Magnetic Sensitivity

Sensitivity class A B C
Pull-in AT range 5-10 10-15 15-20
Available switches 39,40,87 40

This data relates to unmodified Reed switches before mounting. Please refer to the respective single data sheets for sensitivity data and measurement methods for finished assemblies.

Order information

Ordering example

MK18 – 1A39 A – 300 W

MK18 Reed Sensor, 1 form A switch type 39, Sensitivity class A, Cable length 300mm, Termination W

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