Platinum/cobalt resistance thermometer for industrial cryogenic use from 4K to 375K
The R800-6 and R800-7 are industrial Platinum/Cobalt resistance thermometers for industrial cryogenic applications.
Because the platinum alloy contains trace amounts of cobalt, the thermometer has superior cryogenic sensitivity with regard to pure platinum sensors.
- Suited for measurements from cryogenic to room temperature with 1 single sensor
- 2 types:
- R800-6: 4K (-269°C) to 375K (101°C)
- R800-7: 15K (-258°C) to 375K (101°C)
- low heat capacity
- excellent stability
- 4-wire connection
Note that a PtCo resistance thermometer has different resistance values with regard to temperature than a standard Pt100. For explanation of the differences, see page below.
Temperature controllers & programmers for use with Pt/Co resistance thermometers
Specifications
- Measuring element: Platinum/Cobalt dilute alloy
- Measuring temperature:
- R800-6: 4K to 375K
- R800-7: 15K to 375K
- Accuracy: +/- 0.5K in the whole measuring range (see standard resistance table). Sensor is interchangeable
- Resistance value at 0°C: 100 ohm +/- 0.15 ohm
- Sensitivity:
- minimum 0.09 ohm/K at 12K
- maximum 0.40 ohm/K
- Repeatability: within 10mK
- Nominal current: 1 mA DC
- Self-heating characteristic: 4mK/1mA (in liquid nitrogen N2)
- Temperature sensor construction:
- spiral coil type aluminium-oxide ceramic construction
- protective tube: capsule type gold plated oxygen free copper diameter: 2.0mm x length: 23mm
- Lead wire: 4-wire type, polyester covered copper wire diameter: 0.2mm length: 1000mm (JIS C3202-94)
- Response time: 5 seconds at 90% response (0°C to liquid oxygen)
- Maximum ambient temperature: 120°C
Remark:
- The manual of the R800-6 and R800-7 specifies 2 mA DC measurement current. Of course it can be used with lower values like 1 mA DC, because the lower the current, the smaller the self-heating and the more accurate the measurement will be.
- Please note that our Chino DB1000/KP1000/DB2000/DP2000 temperature controllers and programmers measure with a DC current of approx. 1mA.
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External dimensions
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R800-6 and R800-7 reference characteristics resistance value table (4K to 300K)
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Difference between Pt/Co100 and Pt100 resistance thermometers
Pt100 and PtCo100 sensors both have a nominal resistance of 100 ohms at 0°C, but the PtCo100 offers significantly higher sensitivity and resolution specifically at cryogenic temperatures.
The standard Pt100 is designed for a much wider temperature range (typically -200°C to 850°C), while the PtCo100 is specialized for extremely cold applications (-270°C to 200°C).
Key differences between Pt100 and PtCo100
Pt100
PtCo100
Applications:
used widely in general industrial applications
specifically engineered for cryogenic applications (extremely low temperatures).
Operating range:
wide range, generally from -200°C to 850°C.
more specialized range of -270°C to +200°C.
Sensitivity:
lower sensitivity below -200°C
higher sensitivity in the cryogenic temperature range
Temperature coefficient:
standard 0.00385 Ω/Ω/°C coefficient as per the IEC 60751 standard.
different coefficient of 0.003376 Ω/Ω/°C (or 3376 ppm).
Comparison of the temperature dependent resistance values
The resistance-temperature relationship for a standard Pt100 follows the IEC 60751 standard (alpha coefficient of 0.00385 Ω/Ω/°C). The PtCo100 has a different, non-linear characteristic with a specific temperature coefficient of 0.003376 Ω/Ω/°C, designed to provide better performance at very low temperatures.
Note: Specific resistance values for the PtCo100 are highly specialized, and precise values outside of 0°C for this unique material require consulting the manufacturer’s specific data sheets or using their provided calculators.
Below is a table showing the different resistance values between Pt100 and PtCo100 sensors depending on temperature.
Temperature (°C)
Pt100 resistance (Ohm)
PtCo100 resistance (Ohm). Always see manufacturer table for actual resistance value
-269.15 (4K)
approx. 1.5 (extrapolated/outside range)
High sensitivity/resolution in this range. Chino R800: 7.792
-200 (73.15K)
18.5
Chino R800: 25.784
-100 (173.15K)
60.2
Chino R800: 64.012
-50 (223.15K)
80.3
Chino R800: 82.172
0 (273.15K)
100.0
Chino R800: 99.947
26.85 (300K)
110.41
Chino R800: 109.419
