Device and method for monitoring a discharge in a plasma process

Device and method for monitoring a discharge in a plasma process, in particular between electrodes of a cathode sputtering arrangement (13), to which power is supplied by a power generator with a periodically changing output signal of the power generator, having the following steps of: a. detecting at least a first signal path (2) of at least one plasma supply signal (19) within at least a first time range within at least one period of the plasma supply signal, b. detecting at least a second signal path (6) of at least one plasma supply signal (19) within at least a second time range which is at the point corresponding to the first time range in at least one other period of the plasma supply signal, c. generating an identification signal if the second signal path deviates by at least a distance from the first signal path, wherein the distance has a minimum time difference (22) and a minimum signal amplitude difference (21). In particular arcs can thereby be identified in a very reliable and very rapid manner.