JPS6025727B2 - Photoelectric detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoelectric detection device that detects a high-temperature metal object based on the presence or absence of infrared rays.

For example, in steel mills, photoelectric detection devices are often used to detect high-temperature metal objects handled by the steel mills from the standpoint of occupational accidents. The detectors used to detect high-temperature metal objects at this steelworks are particularly called HMDs (HOT, HETAL, DETECTOR), and are photodiodes that are sensitive to infrared rays generated by high-temperature metal objects. A phototransistor, solar cell, or similar photoconductive cell is used as a light-receiving element that converts into an electrical signal. In many recent steel mills, production systems are controlled by computers, and the computers are operated by signals from the HMD. Therefore, in such a highly automated production system, sufficient reliability must be ensured. HM commonly used from subordinates
To briefly explain D with reference to FIG. 1, infrared rays generated by a high-temperature heating material 1 are collected by an optical system 2 and focused on a light receiving element 3 such as a photo or diode.

The light receiving element 3 converts the received light into an electrical signal and sends it to the signal processing circuit 4. This signal processing circuit 4 produces a relay output. By the way, in such a photoelectric type detection device used in a steelworks, there is a risk that malfunctions such as failure of the signal processing circuit, burnout of the light-receiving element due to heat, or deterioration of the conversion element may occur due to the heat generated by the high-temperature metal body handled.

If a photoelectric detector malfunctions in this way, the output will of course be a false signal, so the more automation advances, the more likely it is that the entire production system will go down, leading to a production stop or even another accident. expensive. Therefore, as mentioned above, it is desired to improve the reliability of the device, especially in this detector. therefore,
SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a photoelectric detection device that allows the function of the detection device to be easily checked and, as a result, improves reliability.

To achieve this object, a photoelectric detection device according to the present invention is a photoelectric detection device in which a light receiving element detects infrared rays generated by a high-temperature metal body, and a light emitting element for irradiating infrared rays is provided on the side of the light receiving element. The present invention is characterized in that it includes a switch that controls the supply of current to the light emitting element by closing in response to a check signal, and a display means that operates based on the logical product of the output of the light receiving element and the check signal.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a block diagram schematically showing an embodiment of the present invention, in which infrared rays (light to be detected) collected by an optical system 2 are irradiated onto a light receiving element 3. In FIG. This light receiving element 3 converts the received light into an electrical signal and sends it to a signal processing circuit 4 to obtain a relay output. Furthermore, a light-emitting element 5 is provided, and this light-emitting element 5 is arranged on the side of the light-receiving element 3 so that the light it generates near the light-receiving element 3 is irradiated onto the light-receiving element 3. The light emitted from the light emitting element 5 generates infrared light that is substantially equivalent to the detected light to which the light receiving element 3 is originally sensitive, and for example, a light emitting diode, a lamp, or the like is used. A current supply circuit 6 for operating this light receiving element 5 is provided, and a switch 7 is provided for controlling this current supply circuit 6. By closing this switch 7 on the control side such as a computer, when there is no object to be detected such as a heat material, the light receiving element 3 is provided with the same light as when the object is present.

In this way, by providing the detection device with light that simulates the original light to be detected, the light receiving element 3 and the signal processing circuit 4 are
It is possible to perform a comprehensive check of elements and circuits such as these, or connection lines connecting them. That is, a check signal is generated from the control side, and the switch 7 is closed by this check signal. This check signal and the IJ relay output from the signal processing circuit 4 are logically ANDed, and when this logical product is satisfied, the indicator light is turned on. Then, if the relay output is generated when the check signal is applied, the detection device is normal, and this is indicated by the lighting of the indicator light. In this way, if a large number of indicator lights indicating the operation of each detection device are provided in the control room, it becomes possible to check the operation of a large number of detection devices at once in the control room. The light emitting element 5 is attached, for example, as shown in FIG.

In FIG. 3, the mount 11 has a main cavity 12 through which the light to be detected passes, and a filter is installed in the opening of this cavity to block visible light and allow only the light to be detected (infrared rays) to pass. 13 are provided. This main cavity 12
A light-receiving element 3 is attached to the bottom. Furthermore, a sub-cavity 14 connected to the main cavity 12 is provided, and a light-emitting element 5
The light emitted by the sub-cavity 14 is irradiated onto the light-receiving element 3. If the light-emitting element 5 is attached to the light-receiving element attachment tool 11 of the photoelectric detection device in this way, it is convenient in terms of handling. As described above, according to the present invention, it is discovered that any one of the light receiving element 3, the signal processing circuit, the electrical signal transmission path thereof, the light emitting element and the circuit for operating the light emitting element has failed, and the fail-safe function is activated. can be obtained.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes may be made to the mechanical attachment means and the electric circuit system.
-

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional photoelectric detection device, FIG. 2 is a block diagram showing a photoelectric detection device according to an embodiment of the present invention, and FIG. 3 is a block diagram showing an example of a photoelectric detection device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing the configuration. 1... Heat material, 2... Optical system, 3... Light receiving element, 4... Signal processing circuit, 5...
Light emitting element, 6...Current supply circuit, 7...
・Switch, 11...Mounting tool, 12...
・Main cavity, 13...Filter, 14. ．．・・・
...Sub-cavity. Hair ′ figure hair z figure 3 figure

Claims (1)

[Claims] 1. In a photoelectric detection device that detects infrared rays generated by a high-temperature metal body using a light receiving element, a light emitting element that irradiates infrared rays is provided on the side of the light receiving element, and the infrared rays are applied to the light emitting element by closing in response to a check signal. A photoelectric detection device comprising a switch for controlling the supply of current, and a display means operated by the logical product of the output of the light receiving element and a check signal.