AiVibeThermocouple
A thermocouple is a temperature sensor made of two dissimilar metal conductors joined at one end, which produces a small voltage related to the temperature difference between that measuring junction and the reference junction at the instrument.
Thermocouples work on the Seebeck effect: a temperature gradient along two different conductors generates a voltage of a few to tens of microvolts per degree, depending on the metals. Because the voltage depends on the difference between the hot junction and the cold junction where the wires connect to the instrument, the instrument must measure the cold-junction temperature and apply cold-junction compensation. Standard types, designated by letters such as K, J, T, N, R, S and B, use defined alloy pairs with reference tables in IEC 60584-1.
Thermocouples are rugged, inexpensive, self-powered and able to measure very high temperatures, so they are used in furnaces, kilns, heat treatment, gas turbines, exhaust systems, plastics machinery and many process applications. Type K is the most common general-purpose type, platinum-based types R, S and B serve very high temperatures, and mineral-insulated sheathed constructions protect the wires in harsh environments.
The small signal is vulnerable to electrical noise, and extension or compensating cables of the correct type must be used between sensor and instrument, since ordinary copper wire introduces errors. Accuracy is generally lower than that of RTDs, and thermocouples can drift with age and exposure to high temperatures, so critical measurements need periodic calibration or replacement. Grounded, ungrounded and exposed junctions trade response speed against noise immunity and protection.
Key points
- Two dissimilar metals generate a voltage through the Seebeck effect
- Requires cold-junction compensation at the instrument
- Standard types such as K, J, T and N are defined in IEC 60584-1
- Suits very high temperatures and harsh environments
- Needs matching extension cable and can drift with age
Where AiVibe comes in
AiAmbA IoT is AiVibe's edge protocol layer: it discovers devices and normalises industrial signals, with supported protocols including Siemens S7, Mitsubishi MC, Delta Modbus, OPC UA and MQTT, and driver availability confirmed per installation. Writes to machines are deny-by-default.