Isotech milliK Precision Thermometer

Overview

The Isotech milliK is a precision bench thermometer built to read SPRTs, PRTs, thermistors, thermocouples, and 4–20mA process signals with laboratory-grade accuracy in a compact instrument. Spanning a measurement range of −270°C to 1820°C across its various supported sensor types, it consolidates what would otherwise require several dedicated readout instruments into one multi-sensor precision thermometer.

As part of Isotech’s calibration and metrology instrument range, the milliK is engineered for calibration laboratories and precision temperature measurement applications where traceable, high-resolution readings matter. Seven Star LLC supplies the Isotech milliK to calibration labs and industrial metrology facilities across Oman and the GCC.

Operating Principle

The milliK provides three dedicated input channels — two for SPRTs, PRTs, thermistors, or thermocouples, and one for 4–20mA process signals — reading each with high-resolution circuitry rather than a general-purpose multimeter’s lower-precision input stage. For platinum resistance thermometers, the milliK achieves 5ppm accuracy with 0.00001Ω resistance resolution; for thermocouples, it reaches 2µV accuracy with 0.0001° temperature display resolution, supporting Type B, E, J, K, L, N, R, S, T, and Au-Pt thermocouples.

Engineering Design of the Isotech milliK

The milliK displays readings on an 89mm (3.5-inch) QVGA (320×240) color TFT LCD with LED backlight, showing results in °C, °F, K, ohms, mV, or mA in both numeric and graphical display modes. Connectivity includes 10/100Mbit Ethernet (RJ45), USB 2.0 host, and two RS232 (9-pin D-type) ports, supporting integration into automated calibration systems, data logging setups, or remote monitoring over a network.

Key Features

• Measurement range −270°C to 1820°C (sensor-dependent)
• 3 input channels: 2 for SPRT/PRT/thermistor/thermocouple, 1 for 4–20mA
• PRT accuracy 5ppm, resistance resolution 0.00001Ω
• Thermocouple accuracy 2µV, display resolution 0.0001°
• Supports thermocouple types B, E, J, K, L, N, R, S, T, Au-Pt
• 3.5-inch color TFT LCD display
• Ethernet, USB 2.0, and dual RS232 connectivity
• Numeric and graphical display modes

Industrial Applications

The milliK is used in calibration laboratories and precision metrology facilities across Muscat, Sohar, and Salalah for traceable temperature sensor calibration, verification of process temperature instruments, and reference-grade temperature measurement where standard industrial thermometers lack the required resolution or accuracy.

Across the GCC’s calibration and industrial testing sectors, the milliK’s ability to read multiple sensor types from one instrument — SPRTs, PRTs, thermocouples, and 4–20mA loops — simplifies calibration lab workflows that would otherwise require switching between several dedicated readout units, while its network connectivity supports automated, remote, or logged calibration procedures.

Technical Specifications

Choosing Sensors for the milliK

The overall performance of any precision readout depends on the probe connected to it. For the best results in a calibration laboratory, the Isotech milliK is normally paired with an SPRT or a high-grade reference PRT on one channel and the unit under test on the second channel, allowing direct comparison calibration in a bath or dry-block. Thermocouples are used for the higher temperature ranges, while the 4–20 mA input allows a complete temperature transmitter loop to be checked at the same time as its sensor. Before ordering, list the sensor types, the connectors used on your probes and the temperature range of your calibration work, so that the correct cables and accessories are included.

• Reference probe type and calibration certificate coefficients
• Probe connector types used in your laboratory
• Temperature range of your calibration scope
• Software or data logging requirements

Setting Up and Using the Instrument

Allow the instrument to warm up in a stable room environment before critical measurements. Enter the calibration coefficients of each reference probe exactly as shown on its certificate, and double-check them, since coefficient errors are a common source of mistakes. For thermocouples, use a stable reference junction arrangement. Where a computer is used, the Ethernet, USB and RS232 ports allow readings to be logged automatically for calibration records.

Maintaining Traceability

To keep measurements traceable, recalibrate the readout at the interval required by your quality system, and keep the calibration of the reference probes up to date. Check the reference probes regularly at a fixed point, such as a water triple point cell or ice point, to detect drift between calibrations.

For laboratories accredited to ISO/IEC 17025, the readout, the reference probes and any fixed-point cells each form part of the measurement uncertainty budget, so their calibration certificates, check records and environmental conditions should be kept together. A documented intermediate check routine between external calibrations gives early warning of drift and supports confidence in every certificate the laboratory issues.

Use in Oman and the GCC

The instrument suits calibration laboratories supporting oil and gas, power, water and pharmaceutical facilities, where temperature instruments must be calibrated against traceable standards as part of plant quality and safety programs.

Expanding Beyond Three Channels

The standard instrument has two sensor channels and one current channel. Isotech offers the millisKanner channel expander for larger jobs: each unit adds eight channels, and every channel can be set individually as an SPRT, PRT, thermistor or thermocouple input. Up to four millisKanners can be connected, giving a system of up to 33 channels that is operated from the milliK screen or over RS232. Isotech states that the expansion is made with no loss of accuracy, which makes the combination suitable for calibrating batches of probes in one bath or dry block run.

The milliK can also control Isotech temperature sources, including liquid baths, furnaces and the Basic and Site versions of the dry blocks. It steps through a programmable list of set points and logs the readings without a PC. Time-stamped data is stored in internal memory, which Isotech rates at more than 180 days of measurements, or on a USB drive, and probe data and logged results can be exported to a USB memory stick. A PC lead and software are included with the instrument.

Measurement Details Worth Checking Before Ordering

For resistance thermometers the milliK uses fast current reversal and solid state switching to remove thermal EMF errors, and it corrects lead wire resistance for four-wire probes; three-wire PRTs are also supported. Isotech limits cable runs to 10 Ω per core and 10 nF shunt capacitance, which it equates to about 100 m of typical four-core screened PTFE cable. A four-wire PRT reading takes 0.4 s and a three-wire reading 0.7 s. The two sensor channels are galvanically isolated, and the 4-20 mA input is isolated separately and includes a 24 VDC supply for the transmitter loop.

For thermocouples there are three cold junction modes: internal automatic compensation, an external 0 °C reference, or measuring the junction with a probe on a spare channel. The choice affects uncertainty: for Type K at 600 °C Isotech quotes ±0.04 °C with an ice point reference and ±0.13 °C with internal compensation (initial figures). Recommended working probes that fit the optional carrying case (931-22-102) are the 935-14-61/TTI for -50 to 250 °C and the 935-14-116/TTI for -100 to 450 °C, both with 2 m PTFE cable.

Sourcing from Seven Star LLC

Seven Star LLC supplies Isotech calibration instruments and accessories and can help specify probes, cables and software for your laboratory setup.

Seven Star LLC can also help laboratories plan a complete temperature calibration bench around the readout, including reference probes, comparison baths or dry-blocks, and the connection accessories needed for day-to-day work.

Request a Quote for Isotech milliK Precision Thermometer

Contact Seven Star LLC for a quotation and availability on the Isotech milliK precision thermometer across Oman and the GCC. Our team can help configure the right sensor input combination for your calibration laboratory.

Browse the full Isotech range or see more Temperature Instrumentation products supplied by Seven Star LLC in Oman and the GCC.