The safety beam gate releases an alarm signal when there is an undesirable intrusion in the working space of a machine e.g a press. The signal causes the machine to be switched off. Light sources and receivers connected to a current supply form several light barriers. An electronic control and evaluator arrangement cyclically switches the light sources and conducts the light receiver impulses related to the transmitted pulses to the evaluator. The evaluator only delivers an output signal when it has received a signal from each light receiver at the end of each cycle. The light sources are sequentially energised from the current supply so that they send a large measuring pulse followed by a lower powered control pulse. The amplified receiver signals are conducted to the evaluator via threshold switches which only switch through when this threshold value is attained.
申请公布号
DE2944588(C2)
申请公布日期
1981.11.12
申请号
DE19792944588
申请日期
1979.11.05
申请人
KROHNE MESSTECHNIK GMBH & CO KG, 4100 DUISBURG, DE
