Temperatures that have to be proven
Pasteurisation, sterilisation and cleaning in place are defined by a temperature held for a time, and the record of that temperature is part of the product’s release. The sensor is almost always a PT100, connected with four wires where the record matters. A PT100 reads 127.840 Ω at 72 °C and 146.445 Ω at 121 °C; the PT100 calculator converts in both directions.
The element’s own tolerance is part of the proof. At 121 °C, IEC 60751 allows ±0.31 °C for class AA, ±0.39 °C for class A and ±0.91 °C for class B. A process limit that leaves less margin than the class tolerance cannot be demonstrated with an uncalibrated sensor of that class, whatever the transmitter’s accuracy. This is why critical points use class A or better and individually calibrated probes.
Wiring adds its own error. A three-wire PT100 on 30 m of 0.5 mm² cable reads about 0.14 °C high at 121 °C if the two measuring leads differ by 5 %; with four wires the leads drop out of the measurement. The RTD lead-wire error calculator shows the error for any cable.
Weighing vessels
Batching by weight puts load cells under a vessel. Four 500 kg cells rated 2 mV/V and excited with 10 V give 20 mV at their combined capacity of 2000 kg; with a 200 kg vessel and 1000 kg of product the signal is 12 mV. What the indicator has to resolve is the signal per display division: for 0.2 kg divisions that is 2 µV. The load cell output calculator works this out, and the ADC resolution calculator shows what a given converter can separate.
Pipes, agitators and platforms attached to a weighed vessel carry part of the load or add force of their own. That is a mechanical question no signal calculation answers.
Level and pressure in tanks
Hygienic tanks are measured by hydrostatic pressure through a flush diaphragm. The reading depends on density: 3 m of milk at 1030 kg/m³ is 303 mbar, three per cent more than water. The level to pressure calculator gives the range for any density. A closed or pressurised tank needs a second measurement of the head-space pressure, or a differential transmitter.
Flush-diaphragm transmitters are often used far below their upper range limit. The transmitter accuracy calculator shows what turndown costs once temperature effect and drift are included; the temperature swing during cleaning is larger than in most other industries.
Humidity
Powder handling, tablet coating and packaging depend on air humidity. Air at 20 °C and 50 % relative humidity has a dew point of 9.3 °C. The dew point calculator converts between relative humidity, dew point and the absolute amount of water, which is the quantity a drying process actually removes.
Washdown
Equipment in the wet area is cleaned with hot water under pressure. IP67 means temporary immersion and does not include jets; IP69K is the high-pressure, high-temperature test. A sensor that must survive both needs both ratings. The IP rating decoder explains the codes.
Outside the scope of this site
Hygienic clamp and aseptic fittings are not in the thread identifier, which covers threaded connections only. Conductivity, pH and concentration measurement, and the validation requirements themselves, are also outside these tools.
Updated October 11, 2026