Insights
Equipment
Choosing and caring for sensors, loggers, baths, blocks and references.
How to choose a temperature data logger for mapping and monitoring
Match resolution and accuracy to the acceptance criteria, check the calibration offer, and look at memory, battery, export format and response time before price.
Pt100 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.
Thermocouple 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.
Thermistors: high sensitivity over a narrow range
NTC 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.
Characterising a dry-block calibrator
Before using a dry block for calibration, measure its axial and radial gradients, stability, loading effect and the effect of insert wear — and repeat periodically.
Choosing a liquid calibration bath and its fluid
The 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.
Readouts and bridges for reference thermometers
A reference PRT is only as good as the instrument reading it. Resolution, linearity, measurement current and calibration of the readout all enter the budget.
Ice point, triple point of water and other fixed points
Fixed 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.
Infrared thermometers: what they measure and when to trust them
An IR thermometer measures radiance, not temperature. Emissivity, field of view, distance and reflected background all change the reading — which is why they are for screening, not for GDP records.
Maintaining calibration equipment between calibrations
References drift, baths contaminate, inserts wear, batteries die. A maintenance plan with intermediate checks keeps equipment within its assumed performance and catches failures early.