| 摘要 |
<p>The monitoring system has a pulse generator producing a number of pulses proportional to any state change in the conveyor belt as detected by a sensor. The sensor is an induction coil (15) connected to a pulse generator and detecting the passage of a permanent magnet. The magnet induces a voltage in the coil sufficient to trigger the generator. The coil is shunted by two antiparallel diodes (D1, D2) that limit its output voltage. The coil is connected to one input of an operational amplifier (OP). The amplifier's output is coupled via a diode (D3) to an optoelectronic coupler (OK). A potentiometer (R5) is used to set the quiescent voltage level at the amplifier output.</p> |
