Learning path · 9 articles · about 18 min
Choosing and maintaining temperature equipment
Loggers, sensor classes, sources, readouts and fixed points — what to buy, what the specifications mean and how to keep it all within its assumed performance.
For: Laboratory managers, metrologists and engineers specifying or maintaining measurement equipment.
- 01EquipmentHow to choose a temperature data logger for mapping and monitoringMatch resolution and accuracy to the acceptance criteria, check the calibration offer, and look at memory, battery, export format and response time before price.2 min
- 02EquipmentPt100 tolerance classes explained (IEC 60751)Class AA, A, B and C define the maximum permissible deviation of a platinum resistance thermometer from the standard curve as a function of temperature. They are tolerances, not uncertainties.2 min
- 03EquipmentThermocouple types and tolerance classes (IEC 60584)Types K, J, T, N, E and the noble-metal types R, S, B each have defined EMF curves and tolerance classes 1, 2 and 3. Choose by range, environment and required tolerance.2 min
- 04EquipmentThermistors: high sensitivity over a narrow rangeNTC thermistors offer very high resolution and stability near ambient, which is why many precision loggers use them. Their non-linearity means calibration at several points and a fitted equation.2 min
- 05EquipmentCharacterising a dry-block calibratorBefore using a dry block for calibration, measure its axial and radial gradients, stability, loading effect and the effect of insert wear — and repeat periodically.2 min
- 06EquipmentChoosing a liquid calibration bath and its fluidThe fluid sets the range, the stirring sets uniformity, and depth sets immersion. Ethanol, water, oil and salt each own a range; safety and cleanliness decide among the overlaps.2 min
- 07EquipmentReadouts and bridges for reference thermometersA reference PRT is only as good as the instrument reading it. Resolution, linearity, measurement current and calibration of the readout all enter the budget.2 min
- 08EquipmentIce point, triple point of water and other fixed pointsFixed points realise defined temperatures without a calibrated reference. The ice point (0 °C, ~±0.002 °C) is accessible to any laboratory; the triple point of water (0.01 °C) is the anchor of ITS-90.2 min
- 09EquipmentMaintaining calibration equipment between calibrationsReferences drift, baths contaminate, inserts wear, batteries die. A maintenance plan with intermediate checks keeps equipment within its assumed performance and catches failures early.2 min
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