Anton Paar MKT 50 High-Precision Millikelvin Thermometer

Overview

The Anton Paar MKT 50 is a laboratory-grade high-precision resistance thermometer designed for metrological traceability and primary-level temperature calibration. It operates on the principle of precision four-wire platinum resistance thermometry (PRT), compliant with ITS-90 (International Temperature Scale of 1990), IEC 60751 (industrial Pt100/Pt25.5 sensors), and ASTM E1137 (standard specification for industrial platinum resistance thermometers). Unlike conventional digital thermometers, the MKT 50 functions as a reference-grade bridgeless resistance measuring instrument—capable of resolving resistance changes down to 40 µΩ (0.1 ppm of full scale)—enabling temperature determinations with an uncertainty of ≤1 mK across its full operational range (−260 °C to +962 °C). Its architecture eliminates analog-to-digital conversion drift by integrating a stabilized 400 Ω Vishay Precision Group VHP101 reference resistor and a low-noise, low-current excitation circuit (0.41 mArms), ensuring long-term stability and repeatability required in accredited calibration laboratories and metrology departments.

Key Features

• Reference-grade resistance measurement with 40 µΩ resolution and <0.4 mΩ absolute accuracy at 0–440 Ω range
• Two-channel simultaneous PRT measurement (LEMO 1S304 connectors) supporting dual-sensor comparison calibrations
• Compliance with ITS-90 fixed-point calibration protocols when paired with certified Standard Platinum Resistance Thermometers (SPRTs)
• Integrated Ethernet interface (10 Mbit, PoE-capable) for remote control, automated data logging, and synchronization with Anton Paar DMA™ density meters and SVM™ viscometers
• Stable 0.41 mArms excitation current minimizes self-heating effects in high-stability Pt100 and Pt25.5 sensors
• Graphic LCD display with LED backlight (128×64 pixels) optimized for low-glare lab environments and precise visual verification of readings
• Robust mechanical design (240 × 190 × 110 mm, 2 kg) engineered for both benchtop metrology and transport between calibration sites

Sample Compatibility & Compliance

The MKT 50 is compatible with all standard industrial and reference-grade platinum resistance sensors conforming to EN 60751 (Pt100, Pt200, Pt500, Pt1000) and ITS-90 specifications (including SPRTs with nominal resistances of 25.5 Ω and 100 Ω). It supports four-wire Kelvin connections exclusively—eliminating lead resistance errors—and accepts sensor configurations with thermal time constants suitable for liquid bath immersion, fixed-point cell insertion, and dry-block applications. The instrument meets ISO/IEC 17025 requirements for calibration laboratories and supports audit-ready documentation workflows aligned with GLP and GMP practices. Its firmware implements traceable internal diagnostics, including reference resistor stability monitoring and excitation current validation—critical for FDA 21 CFR Part 11-compliant environments where electronic records and signatures are mandated.

Software & Data Management

Data acquisition and instrument control are managed via native Ethernet communication using TCP/IP protocols. The MKT 50 integrates seamlessly into Anton Paar’s unified software ecosystem—including LabX™ and mPDS™—enabling automated calibration reports compliant with ISO 17025 Annex C and EURAMET cg-18 guidelines. All measurements include timestamped metadata (ambient temperature, battery voltage, excitation current, reference resistor status), stored in CSV or XML formats with cryptographic hash integrity checks. Audit trails record user login events, parameter changes, and firmware updates—supporting 21 CFR Part 11 electronic signature enforcement when deployed with validated LabX configurations. Optional RS-232 or USB-to-serial adapters allow legacy system integration without compromising measurement fidelity.

Applications

• Primary and secondary calibration of industrial Pt100 sensors in accredited metrology labs
• ITS-90 realization at defining fixed points (e.g., triple point of water, freezing point of zinc, aluminum, silver)
• Intercomparison of reference thermometers during inter-laboratory proficiency testing
• Temperature validation of thermostatic baths, ovens, and environmental chambers per ISO 17025 clause 6.4.3
• Traceable temperature input for high-accuracy density (DMA™) and viscosity (SVM™) measurements where thermal expansion correction dominates uncertainty budgets
• Research applications requiring sub-millikelvin stability in cryogenic or high-temperature furnace characterization

FAQ

Does the MKT 50 require external calibration to maintain its stated accuracy?
No—the MKT 50 is factory-calibrated against NIST-traceable standards and includes an internal 400 Ω VHP101 reference resistor with documented long-term drift (<2 ppm/year). Annual verification against a certified SPRT is recommended for ISO/IEC 17025 compliance but not mandatory for routine operation.
Can the MKT 50 be used for direct temperature measurement without a connected sensor?
No—it is a resistance meter, not a standalone thermometer. Accurate temperature values are derived only when connected to a calibrated Pt100, Pt25.5, or other ITS-90-compliant PRT sensor.
Is PoE (Power over Ethernet) supported for continuous lab operation?
Yes—the MKT 50 accepts IEEE 802.3af-compatible PoE (Class 3, up to 15.4 W), enabling single-cable deployment in networked metrology workstations without local power outlets.
What sensor certifications are supported for traceable calibration reporting?
DAkkS, UKAS, and NIST-certified Pt100 sensors (with full uncertainty budgets and CoC) are fully supported. The instrument automatically imports sensor-specific Callendar-Van Dusen coefficients from embedded EEPROM or manual entry.
How does the MKT 50 differ from the MKT 10 in metrological capability?
The MKT 50 provides two-channel measurement, higher resolution (40 µΩ vs. 400 µΩ), lower uncertainty (≤1 mK vs. ≤10 mK), and full ITS-90 fixed-point compatibility—making it suitable for primary calibration, whereas the MKT 10 is optimized for field verification and production QA/QC.