Fluke 9144 Field Metrology Well (25 to 660°C)

A lightweight and easy to use field metrology well that is ideal for performing transmitter loop calibrations, comparison calibrations, or simple checks of thermocouple sensors. This unit is designed for industrial process environments and fast speed temperature. Also, it features 0.25″ (6.35 mm).

Product #
Fluke 9144

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Designed to be a reliable, stable heat source that can be used in the field or laboratory, the unit is easy to use while maintaining stability, uniformity, and accuracy.

Featuring a large LCD, many useful operating parameters including block temperature, current set-point, block stability, and heating and cooling status can be continuously displayed.


  • Lightweight, portable, and fast
  • Heat to 1220°F (660°C) in 15 minutes
  • Built-in two-channel readout for PRT, RTD, thermocouple, 4 to 20 mA current
  • True reference thermometry with accuracy to ±0.01°C
  • On-board automation and documentation
  • Metrology performance in accuracy, stability, uniformity, and loading

Built-in features to address large workloads and common applications

Whether you need to calibrate 4 to 20 mA transmitters or a simple thermostatic switch, a Field Metrology Well is the right tool for the job. With three models covering the range of -13 to 1220°F (–25 to 660°C), this metrology well calibrates a wide range of sensor types. The optional process version provides a built-in two-channel thermometer readout that measures PRTs, RTDs, thermocouples, and 4 to 20 mA transmitters which includes the 24 V loop supply to power the transmitter.

Each process version accepts an ITS-90 reference PRT. The built-in readout accuracy ranges from ±0.01 °C to ±0.07 °C depending on the measured temperature. Reference PRTs for Field Metrology Wells contain individual calibration constants that reside in a memory chip located inside the sensor housing, so sensors may be used interchangeably. The second channel is user-selectable for 2-, 3-, or 4-wire RTDs, thermocouples, or 4 to 20 mA transmitters. For comparison calibration, don't hassle with carrying multiple instruments to the field. Field Metrology Wells do it all as a single instrument.

Traditionally, calibrations of temperature transmitters have been performed on the measurement electronics, while the sensor remained uncalibrated. Studies have shown, however, that typically 75% of the error in the transmitter system (transmitter electronics and temperature sensor) is in the sensing element. Thus, it becomes important to calibrate the whole loop—both electronics and sensor.

The process option makes transmitter loop calibrations easy. The transmitter sensor is placed in the well with the reference PRT and the transmitter electronics are connected to the front panel of the instrument. With 24 V loop power, you are able to power and measure the transmitter current while sourcing and measuring temperature in the Field Metrology Well. This allows for the measurement of as-found and as-left data in one self-contained calibration tool.

Allows for two types of automated thermostatic switch test procedures—auto or manual setup. Auto setup requires the entry of only the nominal switch temperature. With this entry, it will run a 3-cycle calibration procedure and provide final results for the dead band temperature via the display. If you need to customize the ramp rate or run additional cycles, the manual setup allows you to program and run the procedure exactly how you would like. Both methods are fast and easy.

Metrology performance for high-accuracy measurements

Unlike traditional dry-wells, field metrology wells maximize speed and portability without compromising the six key metrology performance criteria laid out by the EA: accuracy, stability, axial (vertical) uniformity, radial (well-to-well) uniformity, loading, and hysteresis. All criteria are important in ensuring accurate measurements in all calibration applications. Field Metrology Well displays are calibrated with high quality traceable and accredited PRTs. Each device (process and non-process versions) comes with an IEC-17025 NVLAP-accredited calibration certificate, which is backed by a robust uncertainty analysis that considers temperature gradients, loading effects, and hysteresis. The display accuracy ranges from ±0.35°C at 788°F (420°C) to ±0.5°C at ±1220°F (±660°C). Each calibration is backed with a 4:1 test uncertainty ratio.

New control technology guarantees excellent performance in extreme environmental conditions. It is stable to ±0.05°C. But this is not all! Thermal block characteristics provide radial (well-towell) uniformity performance to ±0.01°C. Dual-zone control helps these tools achieve axial uniformity to ±0.05°C at 1.6" (40 mm).

Automation and documentation make each unit a turnkey solution

The process versions of field metrology wells have onboard non-volatile memory for documentation of up to 20 tests. Each test can be given a unique alphanumeric ID and will record block temperature, reference temperature, UUT values, error, date, and time. Each test can be easily viewed via the front panel or exported using Model 9930 Interface-it software, which is included with each shipment. Interface it allows you to pull the raw data into a calibration report or an ASCII file. Each test can be easily viewed via the front panel. Use the 1586A Super-DAQ to automate temperature sensor calibration with these wells.

Operation is as easy as 1-2-3

You'll find field metrology wells intuitive and easy to use. Each unit is equipped with a large, easy-to-read LCD display, function keys, and menu navigation buttons. Its "SET PT." button makes it straightforward and simple to set the block temperature. Each product has a stability indicator that visually and audibly tells you the well is stable to the selectable criteria. Each unit offers preprogrammed calibration routines stored in memory for easy recall, and all inputs are easily accessible via the front panel of the instrument. Never buy a temperature calibration tool from a company that only dabbles in metrology (or doesn't even know the word). Designed and manufactured by the same people who equip the calibration laboratories of the world's leading temperature scientists. These are the people around the world who decide what a Kelvin is! We know a thing or two more about temperature calibration than the vast majority of the world's dry-well suppliers. Yes, they can connect a piece of metal to a heater and a control sensor. But we invite you to compare all our specs against the few that they publish.

Small dry wells for big field applications

Packed with functionality and are remarkably easy to use. They are lightweight, small, and quick to reach temperature set points, yet they are stable, uniform, and accurate. These industrial temperature loop calibrators are ideal for performing transmitter loop calibrations, comparison calibrations, or simple checks of thermocouple sensors. With the "process" option, there is no need to carry additional tools into the field. This optional built-in two-channel readout reads resistance, voltage, and 4 to 20 mA current with 24 volt loop power. It also has on-board automation and documentation.

High performance for the industrial environment

Designed for the industrial process environment and fast speed to temperature. They weigh less than 18 lbs (8.2 kg) and have a small footprint, which makes them easy to transport.

Field environment conditions are typically unstable, having wide temperature variations. Each metrology well has a built-in gradient-temperature compensation (patent pending) that adjusts control characteristics to ensure stable performance in unstable environments. In fact, all specifications are guaranteed over the environmental range of 55.4 to 91.4°F (13 to 33°C).


  • Transmitter loop calibrations
  • Comparison calibrations
  • Simple checks of thermocouple sensors

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