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.
9 articles · about 28 min · 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 what calibration is offered, then weigh memory, battery, export and response time.3 min
- 02EquipmentPt100 tolerance classes explained (IEC 60751)Classes AA, A, B and C widen with temperature: Class A is ±0.15 °C at 0 °C but ±0.55 °C at 200 °C. A tolerance class is not a measurement uncertainty.3 min
- 03EquipmentThermocouple types and tolerance classes (IEC 60584)Types K, J, T, N and E each have a defined EMF curve and tolerance classes 1, 2 and 3. The tolerance applies to new wire, not to a year-old thermocouple.4 min
- 04EquipmentThermistors: high sensitivity over a narrow rangeNTC thermistors give high resolution and stability near ambient, which is why precision loggers use them. Non-linearity means several points and a fit.3 min
- 05EquipmentCharacterising a dry-block calibratorBefore using a dry block for calibration, measure its axial and radial gradients, stability, loading effect and insert wear — then repeat periodically.3 min
- 06EquipmentChoosing a liquid calibration bath and its fluidThe fluid sets the range, stirring sets uniformity, depth sets immersion. Ethanol, water, oil and salt each own a range; safety decides the overlaps.3 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.3 min
- 08EquipmentIce point, triple point of water and other fixed pointsFixed points realise defined temperatures without a calibrated reference. The ice point, at 0 °C to about ±0.002 °C, is within reach of any laboratory.3 min
- 09EquipmentMaintaining calibration equipment between calibrationsReferences drift, baths contaminate, inserts wear, batteries die. Maintenance and intermediate checks find those before the next calibration does.3 min
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