In accordance with the invention, this object is achieved by exciting the active electrode with a HF current, measuring and combining values of the partial currents entering the partial electrodes and generating an alarm signal which depends upon {HEAD ~ a comparison} of this combination of the partial currents with {TAIL ~ a pre set limit value} 
with
In accordance with the invention , this object is achieved by exciting the active electrode with a HF current , measuring and combining values of the partial currents entering the partial electrodes and generating an alarm signal which depends upon { HEAD ~ a comparison } of this combination of the partial currents with { TAIL ~ a pre set limit value }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL