The measurement of residual moisture levels in compressed air is carried out by determining the dew point. The maximum permissible values, depending on the application, are defined in the 7 quality classes according to ISO 8573. Of these, Class 1 has the most stringent requirements.
The heart of the new testo 6781 dew point transmitter is the sensor with technology specially developed by Testo. Its exceptional robustness and durability make it extremely resistant to condensation formation and allow for an accuracy of ±3.0 °Ctd at a dew point of 90 °Ctpd. With measurements at these extremely low dew points, the testo 6781 also meets the two most demanding ISO quality classes, corresponding to the requirements of modern semiconductor production (class 1: 70 °Ctd) or pellet drying processes (class 2: 40 °Ctd), for example. For reference:
The absolute humidity in class 1 = 0.003 and in class 2 = 0.12 g of water vapor per m3.
In addition to the metal housing and sensors, the testo 6781 features an external interface for connection to the P2A software, adjustable analog outputs for integration into any industrial automation system, and an optional operational display. As with all testo transmitters, cyclic self-tuning and self-checking functions ensure optimal
process functionality.
