MK38 Recessed Reed Sensors

Introduction

MEDER electronic’s MK38 series consists of recessed reed sensors for non-contact position detection. Designed for press-in mounting in a 9.5 mm (0.375 in) hole, these sensors pair with a corresponding actuator to detect opening, closing, or relative movement without a mechanical contact interface.

The series is notable for its range of reed contact configurations and electrical ratings, allowing the same recessed installation concept to be adapted to different switching requirements.

What it does

An MK38 sensor uses a reed switch that changes state when its actuator is brought into the required operating position. Available contact forms include 1A, 1B, and 1C, supporting normally open, normally closed, and changeover switching arrangements.

Depending on the selected version, the series supports maximum rated power from 3 W to 100 W, switching voltages from 30 V to 300 V, and switching currents from 0.2 A to 1.0 A. Maximum carry current ranges from 0.5 A to 2.5 A.

The devices are specified for operating temperatures from -40°C to +75°C and offer operating lives of 10⁷ to 10⁸ cycles. Maximum operating time is specified from 0.7 ms to 1.1 ms, with maximum release time from 0.05 ms to 0.5 ms.

Applications

• Door, window, and enclosure open/closed detection
• Access-control and building-security sensing
• Cabinet, panel, and equipment-door position monitoring
• Non-contact end-position detection in equipment using a compatible actuator
• Recessed sensing installations where a 9.5 mm mounting hole is available

Design considerations

• The MK38 is intended for press-in installation in 9.5 mm (0.375 in) diameter holes.
• Sensor operation depends on the position of a separate actuator, so mechanical alignment and the intended sensor-to-actuator arrangement should be considered during enclosure design.
• Select the contact form—1A, 1B, or 1C—according to the required circuit behavior in the detected and released states.
• Electrical limits vary across the series. Verify the selected device’s rated power, switching voltage, switching current, and carry-current limits for the intended load.
• Adapter options are available for installation in steel, which may be relevant where the sensor is mounted in ferromagnetic material.
• The specified contact resistance, insulation resistance, capacitance, and breakdown-voltage range should be considered when integrating the sensor into low-level signal or higher-voltage switching circuits.

Availability and further information

The source/distributor and datasheet links on this page provide further information on MK38 recessed reed sensor variants, actuator compatibility, mounting arrangements, and detailed electrical characteristics.