The microK 70 and 125 models are designed for the Primary Temperature Laboratories whilst the microK 250 and 500 models were designed for the Secondary Laboratory as well as a wide range of high accuracy industrial and scientific calibration applications. The instruments use a completely new measurement technique to achieve accuracies better than 0.02 parts per million (ppm). In April 2017 Isotech won a Queen’s Award for Enterprise in the Innovation category for the co-development of the microK, read more in our news section.

When used with a 0°C cold junction reference unit, or by measuring the junction temperature with a PRT on another channel the instrument is capable of low uncertainty precision thermocouple measurements, with a voltage uncertainty of just 0.25μV, equivalent to 0.01°C with a Platinum / Gold Thermocouple at 1000°C.

The microK range consists of four instruments offering a choice of measurement accuracy of 0.07 to 0.5ppm over the whole range, equivalent to 0.07mK to 0.5mK over the whole range of an SPRT with an Ro >2.5Ω. Better at unity ratio.

The instruments in the microK range offer performance characteristics and features which are simply not available elsewhere. Comparable instruments available internationally do not achieve the same accuracy or stability (zero drift characteristics with SPRT measurements are not obtainable in any other instrument), other instruments do not support the same variety of sensors, and offer considerably less operational features. The microK family uses solid state construction with no potentiometers or relays which ensures long term reliability and low cost of ownership, a feature of growing international importance.

Parameter	microK 70	microK 125	microK 250	microK 500
Accuracy Whole Range (SPRT Ro ≥ 2.5Ω) [1]	0.07ppm	0.125ppm	0.25ppm	0.5ppm
Accuracy Ratio 0.95 to 1.05 [2]	0.017ppm	0.03ppm	0.06ppm	0.125ppm
Equivalent Temperature Accuracy [2]	0.017mK	0.03mK	0.06mK	0.125mK
Resolution	0.001mK	0.001mK	0.01mK	0.01mK
Resolution Voltage	10nV	10nV	10nV	10nV
Stability	0ppm/yr [3]	0ppm/yr [3]	0ppm/yr [3]	0ppm/yr [3]
TC (resistance ratio) [4]	0ppm/ ° C [3]	0ppm/ °C [3]	0ppm/ °C [3]	0ppm/ °C [3]
Resistance Range	0-100 kΩ	0-100 kΩ	0-500kΩ	0-500kΩ
Voltage Range (Thermocouple)	±125mV	±125mV	±125mV	±125mV
Internal Resistance Standards	25, 100, 400Ω	25, 100, 400Ω	1, 10, 25, 100, 400Ω	1, 10, 25, 100, 400Ω
Internal Standard	TCR <0.5ppm/°C	²	1, 10Ω <0.6ppm/°C <5ppm/year	"
Resistor Stability	Annual Stability <2ppm/year	"	25, 100, 400 <0.3ppm/°C <5ppm/year	"
Interfaces	RS232, GPIB & USB & Ethernet	"	RS232, GPIB, USB	"
Power	25W maximum, 1.5A (RMS) maximum	"	20W maximum, 1.5A (RMS) maximum	"
Weight	13.3kg	13.3kg	12.4kg	12.4kg