The advantage of using thermocouple:
1. Wide temperature range:
The measurement temperature range of thermocouple is from 0°C to +2200°C, depending on different mark and material.
2. Strong and durable: thermocouple belongs to durable devices with good shock resistance and is suitable for dangerous harsh environment.
3. Fast response: because of small volume, low thermal capacity, thermocouple responds to temperature change fast, especially when the induction junction joint exposed. They could respond to temperature changes within hundreds of milliseconds.
4. No self-heating: as thermocouple does not need to charge power supply, it is not easy to spontaneous heat and its own is safe.
The disadvantages of using thermocouple:
1. Complex signal conditioning: converting thermocouple voltage into usable temperature readings requires a lot of signal conditioning. Signal conditioning has always consumed a lot of design time, improper processing will introduce errors, resulting in reducing accuracy.
2. Low accuracy: in addition to the inherent inaccuracy of thermocouple internal due to metal characteristics, thermocouple’s measurement accuracy could only reach the measurement accuracy of reference junction point’s temperature, generally within 1°C to 2°C.
3. Vulnerable to corrosion: as thermocouple is composed of two different metals, in some working conditions, corrosion may reduce the accuracy over time. Therefore, thermocouple needs protection and normal maintenance is essential.
4. Poor noise resistance: when measuring signal changes at mill volt level, noise generated by stray electric and magnetic fields may cause problems. Stranded thermocouple wire pairs may significantly reduce magnetic field coupling. Electric field coupling can be reduced by using shielded cables or by wiring and shielding in metal conduits.
