Designed and manufactured by our primary standards metrologists, the strain-free sensing element in the 5699 meets all ITS-90 requirements for SPRTs.
After one year of regular usage, drift is less than 0.008 °C (< 0.003 °C is typical). Even lower drift rates are possible depending on care and handling. A fifth wire for grounding is added to the four-wire sensor to help reduce electrical noise, particularly for AC measurements. Finally, you can get an improved version of an old industry-standard Inconel-sheathed SPRT.
The 5699 is constructed with a 0.219-inch-diameter Inconel sheath for high durability and fast response times. Inside the sheath, the sensing element is protected by a thin platinum housing that shields the sensor from contamination from free-floating metal ions found within metal environments at high temperatures. Reduced contamination means a low drift rate—even after hours of use in metal-block furnaces at high temperatures.
If you choose not to calibrate the 5699 yourself, a wide variety of options are available from Fluke Calibration’s own primary standards laboratory, including fixed-point calibrations covering any range between –200 °C and 661 °C.
At Fluke Calibration, we use SPRTs every day. We design them, build them, calibrate them, use them as standards, and know what it takes to make a reliably performing instrument. Why buy from anyone else?
|Temperature Range||–200 °C to 670 °C|
|Nominal RTPW||25.5Ω (± 0.5Ω)|
|Resistance Ratio||W(302.9146 K) ≥ 1.11807 W(234.3156 K) ≤ 0.844235|
|Sensitivity||0.1 Ω/ °C|
|Drift Rate||< 0.008 °C/year (< 0.003 °C/year typical)|
|Repeatability||< 1 mK|
|Self-heating at TPW||< 0.001 °C under 1 mA current|
|Reproducibility||± 0.001 °C or better|
|RTPW Drift After Thermal Cycling||< 0.001 °C|
|Diameter of Pt Sensor Wire||0.07 mm (0.003 in)|
|Lead Wires||Four sensor wires plus grounding wire|
|Diameter:||5.56 mm ± 0.13 mm (0.219 in ± 0.005 in)|
|Length:||482 mm (19 in)|
|Insulation Resistance||> 100 MΩ at 661 °C > 1000 MΩ at 20 °C|
|1911-4-7||PRT Calibration, –200 °C to 660 °C, NVLAP Accredited|