Patent ID: 7301136

Claim:
Method for operating a photoelectric sensor arrangement, said sensor arrangement comprising a pulsed light emitting first module, a light receiving and converting second module and a level judging and/or processing third module, said method comprising the steps of: sending periodically light pulses from the first module towards the second module, directly or indirectly, producing an analogue potential signal corresponding to the received light at said second module and transmitting said signal to the third module through a coupling capacity, processing the analogue signal at said third module in synchronism with the light pulses, and providing an evaluation or control information or signal depending on said processing results, method characterised in that it comprises the steps of: before transmission to the third module ( 4 ), inverting the analogue signal produced by the second module ( 3 ) and shifting or offsetting said inverted signal by a value equivalent to the maximum absolute value or maximum negative value (A 1 ) reached by said inverted analogue signal during the concerned period, and at the third module ( 4 ), measuring said inverted and shifted analogue signal at least once between two successive light pulses and processing the measured value(s).