| 摘要 |
A servo system includes a servo motor which drives a controlled member. The controlled member has a slider and actuating members thereon. The slider moves across a slide-wire and provides a feedback signal representative of the position of the controlled member. An amplifier receives an input signal, representative of a process variable, and the feedback signal, and generates a difference signal, representative of the difference therebetween, for driving the servo motor. The actuating members trip limit switches as the controlled member reaches predetermined limits of travel. The limit switches are serially connected in the servo motor circuit and each is shunted by a diode. The diode allows a difference signal to be applied to the servo motor after its associated limit switch has been tripped, only if the difference signal is of a polarity which would effect the movement of the controlled member away from the tripped limit switch.
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