JPS5920971B2 - Operation confirmation device for defect detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation confirmation device for a defect detection device for a strip material.

Inspection of defects in the strip material is carried out by running the strip material or by scanning a defect detector in the width direction of the strip material.

There are various methods of defect detection, but whatever method is used, it is necessary to check whether the defect detection operation is being performed normally. Conventionally, this check was carried out by having a person stop the equipment and inspect it one by one, or by running a strip of material with pseudo-defects and testing whether a defect detection signal was output. . The former method requires a lot of manpower and is time-consuming, and the inspection of the strip material must be stopped during the inspection, while the latter method does not require much manpower, but the inspection of the material to be inspected must be stopped during the check. Can not. Therefore, it is an object of the present invention to enable the operation of a defect detection device to be checked at any time and at any time during the actual inspection.

As mentioned at the beginning, when detecting defects in strip materials, there is relative movement between the material to be inspected and the defect detector, and even when there is no defect in the material to be inspected, the defect detector detects the normal condition of the material. A ground detection signal due to unevenness is output, and a defect appears as a signal that protrudes above the ground detection signal or falls below the level of the ground signal.

In either case, whether the defect detection signal protrudes above the ground signal or falls below, if the DC component of the signal is cut, the output signal of the defect detector becomes a signal as shown in Figure 1, and the level l By sorting out the signals according to the method, it is possible to extract only the defect detection signal. In order to confirm the operation of the defect detection device, the present invention provides a ground signal B in addition to level L in FIG.
When checking the operation during an inspection with a level u from which a defect can be taken out, the setting level of the level selector is switched from l to u, and at this time the defect detection device If a defect detection signal is issued, it can be immediately confirmed that the device is operating normally.

The present invention will be explained below with reference to Examples. In FIG. 2, reference numeral Z denotes a strip material to be inspected, which is run in a direction perpendicular to the plane of the drawing, 21 to 2n are defect detectors, and 3 is a light source that illuminates the strip material z from the back.

The defect detector forms an image of the strip material Z and scans the image plane in the width direction to obtain a video signal as shown in Fig. 1.
Each of 1 to 2n divides the entire width of the strip material and scans one section thereof. 41 to 4n are level selectors connected to the corresponding defect detectors 21 to 2n, and 6 is a level setter for comparison, in which two set voltages are set, and which one is selected by the changeover switch S. This voltage can be applied to the comparators 41 to 4n as a reference level for comparison.

The comparators 41 to 4n output a defect detection signal when the output signal of the corresponding defect detector exceeds a set level, and this signal is sent to the corresponding display device 51 to 5n to display the defect and is also sent to the recording device R. It is recorded along with a distance mark representing the running length of the strip material z. Since the defect detection signals outputted from the comparators 41 to 4n are instantaneous, they cannot be clearly seen in X even if a display lamp is turned on, for example. Therefore, each of the display devices 51 to 5n uses a one-shot circuit and is triggered by the defect detection signal so that the indicator lamp remains lit for a certain period of time. When the switch S is set to the contact L side, the level indicated by l in FIG. 1 is applied to the comparators 51 to 5n, and normal inspection is performed. -4n is applied to confirm the operation of the defect detection device.

In this case, since the defect detectors 21 to 2n are constantly outputting fault signals, the comparison circuits 41 to 4n are also constantly outputting signals, and the display devices 51 to 5n are supposed to display a defect detection display all at once. Therefore, if there is a display device that is not displaying at this time, it can be seen at a glance that there is a failure in the corresponding defect detector or comparator. Therefore, the operation check can be completed in an instant, and there is no problem with the test even if it is performed at any time during the test. The device of the present invention has the above-mentioned configuration, and can check the operation of the defect detection device in a very short time simply by switching the comparison level.Furthermore, even if there are a large number of defect detectors, the operation can be checked all at once. There is no need to run strips of material with pseudo-defects, so there is no need to disturb the inspection process.

[Brief explanation of the drawing]

FIG. 1 is a waveform diagram of an output signal of a defect detector, and FIG. 2 is a block diagram showing an embodiment of the present invention. 21~2n...Fault detector, 41~4n...
... Comparator, 51-5n ... Display device, 6.
...Level setting circuit.

Claims (1)

[Claims] 1. A defect detector scans the surface of a material to be inspected, and the output of the defect detector is level-sorted to detect defects, and the sorting level is a level from which a defect detection signal is extracted;
A device for checking the operation of a defect detector, characterized in that it is switchable between two levels at which a formation detection signal can be taken for checking the operation of the defect detector, and is provided with a display device for level-selected signals.