Abstract:
A load driving circuit in which an emergency switch for forced stoppage and a service switch for controlling current are connected in series with a load power-feeding circuit. An emergency switch (SWA) and a service switch (SWB) are connected in series with the load power-feeding circuit and the switch (SWB) is periodically turned off for a short time in accordance with the control signal (X) of a service switch control circuit (30). The turn-off state of the switch (SWB) is monitored through the output signal (AC) of a monitoring circuit (40). When the output signal (AC) of the circuit (40) is not generated for more than the off-delay time of an off-delay circuit (21), the control signal (Z) of an emergency switch control circuit (20) is stopped and the switch (SWA) is forcedly turned off.
Abstract:
A fail-safe timer circuit which does not generate such an erroneous output that shortens delay time when a fault occurs and an on-delay circuit. The timer circuit comprises an oscillator circuit (11) which generates a timer output from the cathode terminal of a PUT prescribed period after an input signal (VIN) is received and a monitoring circuit (12) which monitors the operation of the oscillator circuit (11). The on-delay circuit comprises a latch (13) which has a first terminal (a) for receiving the input signal (VIN) and a second terminal (b) for receiving an output signal (VO) that the monitoring circuit produces only when it is confirmed that the oscillator circuit (11) is normal by detecting a fall of a cathode terminal voltage of the circuit (11). The latch generates an output signal only when both the input signals are higher in level than the power supply potential, and maintains the state.
Abstract:
A sensor capable of confirming the stop of revolution of a motor inclusive of rotation due to inertia. Signal input lines (A, B, C) are connected to three power feed lines (u, v, w) of an A.C. three-phase motor. A high frequency signal current is supplied to one of the power feed lines, and the difference between current values flowing through the other two power feed lines is extracted from the signal input lines connected to these two power feed lines and is used as the output for a sensor portion (3). Threshold value computation processing of this sensor output is executed by a signal processing circuit (7) and the result of this threshold value calculation output is output as a judgement output (P1) for judging the motor revolution or non-revolution from an ON/delay circuit (8).
Abstract:
An acceleration sensor which detects acceleration by utilizing magnetic coupling. A mass section (3) is displaceably supported by a frame (2) through supporting beams (4). A first planar coil (5) is provided on the section (5), and a second planar coil (8) is so provided as to face to the coil (5) at an interval. A transformer is constituted of the coil (5) as a primary coil and the coil (8) as a secondary coil. The sensor detects acceleration by detecting the variation of the distance between the coils (5 and 8), namely, the displacement of the mass section (3) by utilizing magnetic coupling.
Abstract:
A device for confirming the stop of a motor, particularly a rotation sensor for extracting the rotation signals of the motor. In the first invention, a high-frequency current signal is supplied to the winding of a tachometer generator incorporated in a motor, and a modulated signal obtained by modulating the high-frequency signal with the output signal of the tachometer generator is output from the rotation sensor to direct the rotation of the motor. In the second invention, the rotation of the motor is extracted after converting the rotation into the variation of the oscillation frequency of an oscillator by utilizing a transducer coil as part of the oscillator. In the third invention, the rotation of the motor is extracted after converting the rotation into the variation of the terminal voltage of a resonance circuit by means of the resonance circuit incorporating the transducer coil.
Abstract:
This invention relates to a thin and compact galvanomirror produced by using semiconductor fabrication technology. A flat movable plate (5) and a torsion bar (6) for rotatably supporting this movable plate (5) are integrally formed on a silicon substrate (2) by using semiconductor fabrication technology, and a flat coil (7) and a total reflection mirror (8) are formed on the upper surface of the movable plate (5). Further, glass substrates (3), (4) are disposed on the upper and lower surfaces of the silicon substrate (2), and permanent magnets (10A, 10B and 11A, 11B) for causing magnetic fields to act on the coil (7) are fixed at predetermined positions of these glass substrates. The rocking angle of the movable plate (5) is varied depending on the balance of the resulting magnetic force and the torque by controlling the quantity and direction of the current flowing through the coil (7).
Abstract:
An on-delay circuit using a fail-safe electronic circuit. An input signal higher than a power source potential is inputted to a PUT oscillation circuit. A pulse signal generated with a predetermined time constant is once converted to a level within the range of the power source potential by a level conversion circuit. This signal is inverted and differentiated at its leading edge. The input signal of the PUT oscillation circuit is applied to one input terminal of a fail-safe two-input window comparator and the differential signal is inputted to the other input terminal for self-retention. An output of a logic value 1 is generated from the window comparator with a predetermined delay time. Accordingly, there is provided a fail-safe on-delay circuit the delay time of which is not reduced due to breakdown of a circuit constituent element.
Abstract:
A device for detecting the presence of a vehicle on a track, which includes a first fail-safe AND circuit that converts a local signal applied to a specific section of the track and a track signal into phase decision signals that vibrate with a reference voltage level as a center, and that generate an output depending upon the logical product of the two phase decision signals when the two phase signals are in phase, and a second fail-safe AND circuit that generates a vehicle signal depending upon the logical product of the output of said first AND circuit and an output of a fail-safe level decision circuit that generates the output provided that the voltage level of the track signal is greater than a predetermined value, when the above two outputs are simultaneously generated.
Abstract:
An emergency stop switch and an emergency stop switch circuit which are used for stopping a machine in case of emergency. The emergency stop switch (10) has a transformer-like structure provided with a first core member (14) wound with first and second windings and a second core member (15) which is usually brought into contact with the first member (14) by means of a spring and is separated from the first member (14) when a push-button (16) is pressed. The emergency stop switch circuit is constituted by connecting a plurality of emergency stop switches (10) in series.
Abstract:
An apparatus for automatically controlling the operation of a slide of a fail-safe press. The movement of the hands of a worker in/out of dangerous areas (D and DN) above the bolster of the press is detected on the basis of the output generation modes of two light curtains (5 and 21). When the movement of the hands of the worker out of the dangerous areas (D and DN) is detected a signal which permits the descending operation of the slide is generated.