| 摘要 |
An analogue and/or digital control system is used to improve the precision and control of the movement of hydraulic or pneumatic cylinders (40) using on-off and/or proportional type electromagnetic valves (38, 39). A pulse width-modulated signal generated by a control circuit (1, 2) is regulated by a CPU (28) programmed to divide the signals into a suitable number of signal portions, so that the two electromagnetic valves controlling the cylinder can be opened and closed very quickly. An optical coupling circuit (33, 36) is present between the control circuit exit at the CPU and each transistor (34, 37). The transistors include an electronically activated light-emitting component connected to a power circuit (32), resulting in emitted light that is modulated by the pulse width-modulated signal, and this is received by a light-sensitive component without an external power source in order for the component to generate an exit signal in the form of a voltage modulated by the pulse width-modulated signal. This exit signal is applied as a control voltage between the control electrodes and sources in each of the transistors. Electromagnetic valve pre-magnetisation and pulse control allow high precision cylinder movement and also enable cylinder movement to be quickly reversed in order to oppose forces that can act on the cylinder when it is at rest or moving in a single- or twin-action system. Figure 1 shows a circuit diagram of an analogue control system. (1, 2) Control circuits(3) CPU circuit(4) Safety relay(5) Solar cell(6) Hydraulic-pneumatic system circuit(7) Sensitivity setting device(8) Device for setting maximum cylinder length(9) Device for setting minimum cylinder length(10) Control value setting device(11, 12) Voltameters(13) Inverted summation amplifier(14) Inverted amplifiers(15, 16) Comparators(17) Sensitivity setting device(18) Device for setting maximum cylinder length(19) Device for setting minimum cylinder length(20) Control value setting device(21, 22) Voltameters(23) Inverted summation amplifier(24) Inverted amplifier(25, 26) Comparators(27) Display(28) CPU(29) Circuit board(30, 31) Relays(32) Power circuit(33) Solar cell-type optical coupling(34) Transistor(35) Transistor power circuit(36) Solar cell-type optical coupling(37) Transistor(38, 39) Magnetic valves(40) Cylinder(41) Position sensor |
