| 摘要 |
PURPOSE:To make operations easier by providing a control system to drive electromagnetic valves on a side where the direction of action is judged from command signals according to operating amounts and synchronously with pulse signals obtained by comparing triangle wave signals with command signals. CONSTITUTION:An automatic/manual switch 77 is set to the manual or automatic side, and an operating lever is operated to rising or lowering side. Whereupon, a potentiometer 27 is operated to generate command signals. The acting direction of boom is judged by any one of comparators 46 and 47 of a discriminator 45 from command signals to output signals, and the switch 63 of a driver 60 is turned ON. Command signals are put in the comparators 55 and 56 of a comparator 54 and compared with triangular wave signals from a triangular wave signal generator 53, and pulse signals are outputted from any one of the comparators 55 and 56. ON/OFF operations of the switching element 61 are repeated by pulse signals, and the exciting and demagnetizing operations of any one of solenoids 40 and 41 are repeated. the electromagnetic valve 39 is then switched and the boom cylinder is extended or contracted.
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