Zero point correction circuit of load meter

Abstract

The present invention relates to a zero point correction circuit for a load meter used for a press machine or the like, and more particularly to a configuration with which a zero point correction is made a plurality of times after a predetermined amount of time elapses, after press processing is performed, and a zero point correction value is set by calculating an average value of measured values. The predetermined amount of time is measured, for example, with an internal timer or the like, a sampling process is performed after the predetermined amount of time elapses, and an average value of sampled values is calculated and set as a zero point correction value, whereby an accurate zero point correction value can be obtained.

Description

technical field [0001] The present invention relates to a zero correction circuit of a tonnage gauge used in a press or the like. Background technique [0002] When pressing a material with a press, a tonnage gauge is installed that detects the load generated by the press with a sensor and displays the load. For example, as disclosed in Japanese Patent Laid-Open Publication No. Hei 11-114641, a deflection sensor is provided on the body to detect deflection during pressure driving, and the load is calculated from the output of the sensor and displayed on the tonnage gauge. [0003] Such a tonnage gauge used on a press detects the load generated by the machine and displays it, and the detected data must exactly match the load generated by the press. Therefore, in order to accurately detect the output of the sensor, the zero point correction of the tonnage is performed every time the pressure is driven. For example, a timing signal is supplied from a rotary cam of a press eve...

AI Technical Summary

Problems solved by technology

[0004] However, in the conventional method, the timing signal supplied from the rotary cam is a fixed timing after the end of the pressure drive, and when the sensor signal is unstable at the time of detection, accurate zero point correction cannot be performed.

In particular, although the sensor detects deflection during material processing when the head of the press is lowered, the press is also deflected when the head reaches the top dead center afterwards.

Therefore, the detection signal from the sensor is unstable, and correct zero point correction cannot be performed.

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