| 摘要 |
PURPOSE:To enhance reliability against vibration and the like by constituting a sensor by a permanent magnet and a Hall element, and sensing the load of a press machine through the analog output voltage in response to a relative distance. CONSTITUTION:A load sensor 4 is constituted by the permanent magnet 15 and the Hall element 9. The relative distance between said magnet and hall element varies in response to the amount of extension of a frame of the press machine. The output of the sensor 4 is inputted to a sample and hold circuit 20 and a peak hold circuit 21 via a differential amplifier 18 and a temperature compensating circuit 19. The outputs of the sample and hold circuit 20 and the peak hold circuit 21 are computed in a differential amplifier 25, then the result is converted into tonnage unit in a load converter 26. The converted signal is converted into digital quantity in an A/D converter 27 and displayed by a display 28. When the output of the load converter 26 exceeds the output of a setting device 29, a display lamp 31 is actuated, a contact point 32 is also actuated, and the press machine is stopped. |
