Switch device monitoring circuit for proximity-controlled switch - uses fault and/or condition indicator detecting voltage across switch or measuring resistance to indicate fault or switch condition

摘要

The circuit monitors the switch device and as external conductor (2, 3) coupled to the latter using a fault and/or condition indicator (6)connected across the switch terminals, for detecting a fault and/or the condition of a proximity indicator incorporated in the switch device controlling as electronic switch element. The fault and/or condition indicator periodically reverse the supply voltage for the switch device with detection of the voltage drop across the switch device or a measuring resistance, to detect a fault and/or the proximity indicator condition. Pref. the reversal of the supply voltage is only initiated when the proximity indicator fails to respond for a given interval. USE - For monitoring function of electronic switch device used in measuring, control and regulating circuits.