E. Dold & Söhne GmbH & Co. KG

Tel.: +49 7723 654-0
E-Mail: dold-relays@dold.com

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Tel.: +49 7723 654-454
E-Mail: ab@dold.com

Direct contact for technical questions

Tel.: +49 7723 654-459
E-Mail: rv@dold.com

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Tel.: +49 7723 654-455
MK 9151N

Level Sensing Relay

MK 9151N


Auxiliary voltage

Response value

Terminal type

Response and release delay

Approvals and Markings


  • 0054100
  • MK9151N.12 2-450K AC230V 0,2-20S
Level monitoring and control for conductive liquids and powders, e.g. maximum and minimum... more

Product description

  • Level monitoring and control for conductive liquids and powders, e.g. maximum and minimum filling levels, overfilling and protection against dry running
  • Monitoring and control of the mixing ratio of conductive liquids
  • General resistance monitoring tasks, e.g. limit temperature detection with PTC
  • Contact protection relay with time delay

Technical specifications

Width: 22,5 mm
Measuring range max.: 450 kΩ
Auxiliary voltage: AC, DC
Classification: Füllstandsüberwachung
Operate delay: Yes
Output contacts: 2 x 1 C/O contacts
Enclosure design: Distribution board
Type: MK 9151N


  • According to IEC/EN 60255-1
  • 3 probe connections for 2-point and 1-point level control
  • Also for use as moisture detector
  • High interference resistance of the Measuring Circuit, which is isolated from the mains
  • Max. wire length to the probes: 3000 m
  • Large setting range: 2 ... 450 kΩ this permits differentiation between fluid and foam
  • Separately adjustable response and release time delay 0.2 ... 20 s for MIN- and MAX-level
  • Programmable for:
    - 2 separate controllable output relays for MIN and MAX level
    - Common controlled output relays for 2-point hysteresis level control
    - Open circuit operation
    - Closed circuit operation
  • Measuring Circuit for probes works with internally generated AC voltage (approx. 30 Hz), electrolytic behaviour does not occur in the liquid
  • For auxiliary voltages of 24 ... 415 V AC or 24 V DC
  • LEDs for operation and state of contact
  • 2 changeover relays with 1 changeover contact each
  • IL 9151 and SL 9151 with safe separation according to IEC/EN 61140, IEC/EN 60947-1
  • Devices available in 3 enclosure versions:
    IL 9151: Depth 59 mm, with terminals at the bottom for installation systems and industrial distribution systems according to DIN 43880
    SL 9151, MK 9151N: Depth 98 mm, with terminals at the top for cabinets with mounting plate and cable duct
  • IL/SL 9151: 35 mm width
    MK 9151N: 22.5 mm width