Spray jet function monitoring method e.g. for painting system

摘要

The method involves deriving a first signal (11) from the noise in the vicinity of the spray jet (2) and analyzing the signal to evaluate the function of the spray jet. A second signal (12) is derived from the noise in the wider region surrounding the spray jet. A useful signal (14) can be isolated from the first and second signals and analyzed to evaluate the spray jet functionality. The noise is digitized and the useful signal is isolated using a compensation circuit. The useful signal is compared with a reference and the degree of similarity (16) indicated.