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Average temperature measurement Prothermo NMT81

Prothermo NMT81 - Average temperature measurement ©Endress+Hauser

Precise average temperature measurement

Prothermo NMT81 measures the average temperature of a medium and can optionally identify the water level. With an optional 2m long capacitance sensor, the water level is measured continuously delivering current water level information at any time. With its highly precise average temperature measurement, the NMT81 is perfectly suitable for custody transfer and inventory monitoring together with tank gauging such as Proservo NMS80, NMS81, NMS83, Micropilot NMR81, NMR84 and TankSideMonitor NRF81.

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  • Benefits

    • Precise asset management thanks to up to 24 RTDs

    • Corrosion-resistant process parts

    • Minimize tank construction cost through 1-1/4” sized nozzle

    • Easy installation

    • Waterproof and dust proof housing

    • Reduced downtime thanks to redundant...

  • Field of application

    • For precision average temperature and water bottom measurement

    • Process connection: Flanges from 1-1/4“

    • Temperature: -40 to +60°C (-40 to +140°F)

    • Measuring distance: 100m (328.08ft)

    • Total accuracy: ± 0.036°C(±0.06°F) with 5pt. temperature calibration

    • ...

Features and specifications



  • Measuring principle

    Level radar

  • Characteristic / Application

    Lens antenna, 80GHz: High precision measurement for for storage tanks up to 30 m (98ft)

  • Specialities

    Custody transfer level measurement

    Measurement close to tank wall

  • Supply / Communication


  • Accuracy

    up to 0.5 mm

  • Ambient temperature




    For calibration to regulatory



  • Process temperature



  • Process pressure absolute / max. overpressure limit

    Vacuum.....16 bar abs

  • Main wetted parts

    316L, PTFE

  • Process connection



    Flange w/ Alignment tool:




    UNI-Flange w/ Alignment tool:


  • Max. measurement distance

    70 m (230 ft)

    For calibration to regulatory standards:

    30 m (98 ft)

  • Communication


    Fieldbus: Modbus RS485, V1, HART

    Analog 4-20mA output (Exi/ Exd)

    Relay output (Exd)


    Analog 4-20mA input (Exi/ Exd)

    2-, 3-, 4-wire RTD input

    Discrete input (Exd, passive/active)

  • Certificates / Approvals


  • Safety approvals

    Overfill protection WHG


  • Design approvals

    EN 10204-3.1

    NACE MR0175, MR0103


  • Metrological approvals and certificates

    OIML, NMi, PTB

  • Options

    Redundant fieldbus

    Alu-coated or 316L housing

    Weather protection cover

    Adjustable mounting seals

  • Application limits

    Maximum measuring range is

    dependent on the tank form and/
    or application

    Strong condensate or build-up

Documents / Manuals / Software

Accessories / Spare parts

Order code
  • 21
    • Nr 21 Order code 71312582

      O-ring, housing, 177.39x3.53, TG

      Material: FVMQ, PTFE coated. Usage: housing F35/36/37/38, NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 19
    • Nr 19 Order code 71312589

      Housing filter, PTFE, NMR8x, 2 pcs.,TG

      Consists of: 1x pressure compensation plug M18, 316L. 1x filter plug metal M12, 316L. 1x pressure compensation filter. Usage: housing F36/38, NMR81/NMR84.

  • 14
    • Nr 14 Order code 71312592

      Blind plug, M20, 316L, O-ring EPDM, TG

      Consists of: blind plug, O-ring 18.0x2.0. Usage: housing F35/36/37/38, NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 15
    • Nr 15 Order code 71312594

      O-ring, blind plug, M20, EPDM, 5pcs., TG

      Usage: housing F35/36/37/38, NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 20
    • Nr 20 Order code 71312596

      Front cover Alu, sight glas, gasket

      Material: aluminum. Consists of: cover, O-ring FVMQ, PTFE coated. Usage: housing F35/36, NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

    • Nr 20 Order code 71312607

      Front cover 316L, sight glas, gasket

      Material: 316L. Consists of: O-ring EPDM, clotted. Usage: housing F37/38. NMR81/NMR84, NRF81, NMS81/NMS83.

  • 17
    • Nr 17 Order code 71312627

      Cover clamp, 2 pcs., TG

      Usage: housing F35/36/37/38. NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 37
    • Nr 37 Order code 71324756

      Terminal set, I/O module, Push-in, TG

      Consists of: complete terminal set. Usage: NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

    • Nr 37 Order code 71324757

      Terminal set, I/O module, screw type, TG

      Consists of: complete terminal set. Usage: NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 40
    • Nr 40 Order code 71312638

      Display set, RS485, holder, TG

      Consists of: operation-module, A300, optical buttons, display holder, fixing ring, cover. Usage: NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 41
    • Nr 41 Order code 71312640

      Display holder, fixing ring, TG

      Consists of: fixing ring, holder. Usage: NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 31
    • Nr 31 Order code XPN0036-

      Electronics, mainboard

      Usage: NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • 33
    • Nr 33 Order code XPN0031-

      I/O Module NMR81/84, NRF81, NMS80/81/83

      Usage: NRF81, NMR81/NMR84, NMS80/NMS81/NMS83.

  • .
    • Nr . Order code 71067434

      Modification name plate, non Ex

      Blank. To fill in the new order code when a non Ex instrument has been modified. Usage: FMB50/FMB51/FMB52, FMR230/FMR231, FMR240/FMR244/FMR245, FMR250,FMR530/FMR532,FTL50/FTL50H/FTL51/ FTL51C/FTL51H, FTL70/FTL71, FTL80/FTL81/ FTL85, NMR81, PMC51, PMC71, PMP51/PMP55.

  • 0
    • Nr 0 Order code 71285499

      Seal, adjustable, DN50, FKM

      DN50 PN10-16. Material: FKM. Usage: NMR81.

    • Nr 0 Order code 71285501

      Seal, adjustable, DN80, FKM

      DN80 PN10-40. Material: FKM. Usage: NMR81.

    • Nr 0 Order code 71285503

      Seal, adjustable, ASME 3"/JIS 80A, FKM

      ASME 3" 150lbs / JIS 80A 10K. Material: FKM. Usage: NMR81.

    • Nr 0 Order code 71292751

      Weather protection cover NMR8x, NRF8x

      Material: 316L. Usage: NMR81/NMR84, NRF80/NRF81.

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