摘要 |
Apparatus for monitoring strip loop position, having a plurality of light sources and a corresponding plurality of photo-detectors spaced from each other in the strip loop reservoir on opposite sides of the strip loop path; each photo-detector is connected to the input of a corresponding photocell amplifier which is normally biased to be driven to positive or negative saturation as a function of the input voltage applied to the photocell amplifier. The outputs of all the photocell amplifiers are coupled together through a summing junction to the input of an output amplifier for amplifying the voltage and current signals appearing at the summing junction. Display and/or control means are coupled to the output of the output amplifier.
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