| 摘要 |
1528131 Automatic control R L PARR 17 Sept 1975 [11 Oct 1974 17 April 1975] 381 38/75 Heading G3N [Also in Division H2] In a follow-up control system the voltage at the slider 6 of a potentiometer 8, coupled to an hydraulic valve, (not shown), of a crane, is combined at A with the voltage at a slider 12 of an operatorpositioned potentiometer 10. The voltage at A is applied to a differential amplifier Q 1 , O 2 the outputs of which through transistors Q3-Q5 control the operating duration of sequenced timers 30, 32, 34. The outputs 40, 42 from the timers are applied to bridge-connected transistors Q6-Q9 whereby a motor 2, positioning the hydraulic valve, is energized, in a forward, braking and reverse sequence, in accordance with the operating durations of the timers. |
