| 摘要 |
A system for controlling the operating speed of a can machine having an input conveyor for temporarily storing cans while moving them along a path toward the machine includes a metal wire capacitance sensor. The wire may be formed in a repeating pattern and serve as an area mass sensor. The capacitance formed by the sensor wire and the can is connected in a capacitance bridge circuit which is excited by an oscillator. A detector circuit coupled to the bridge circuit generates an output signal representative of the number of cans in the conveyor. Output drive circuitry including an optical coupler for isolating the detection circuitry from the machine under control, transmits a signal for a desired control function to a remotely located variable speed drive controller for controlling either the machine to which the cans are being fed or a machine which is feeding the cans to keep the size of the can queue at a desired value.
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