JPH0368045U

JPH0368045U -

Info

Publication number: JPH0368045U
Application number: JP13033789U
Authority: JP
Priority date: 1989-11-07
Filing date: 1989-11-07
Publication date: 1991-07-03

Description

[Brief explanation of the drawing]

第１図は本考案の実施例を示す物品点灯回路の
ブロツク図、第２図はその具体的ブロツク図、第
３図は第２図の物品検出回路における各点での動
作波形図、第４図は第２図の物品検出回路の動作
を説明するためのフローチヤートである。第５図
は従来のレーザー方式の物品検出装置を説明する
ための要部の正面図、第６図はその平面図である
。１……加熱炉、２……物品、４……投光手段、
５……受光手段、６……レーザー光、８……立ち
上がり判定回路、９……立ち下がり判定回路、１
０……出力制御回路。 FIG. 1 is a block diagram of an article lighting circuit showing an embodiment of the present invention, FIG. 2 is a detailed block diagram thereof, FIG. 3 is an operation waveform diagram at each point in the article detection circuit of FIG. 2, and FIG. This figure is a flowchart for explaining the operation of the article detection circuit of FIG. 2. FIG. 5 is a front view of a main part of a conventional laser type article detection device, and FIG. 6 is a plan view thereof. 1... heating furnace, 2... article, 4... light projecting means,
5...Light receiving means, 6...Laser light, 8...Rise determination circuit, 9...Fall determination circuit, 1
0...Output control circuit.

Claims

[Claims for Utility Model Registration] Light projecting means that intermittently projects laser light across a fixed position of an article path in a high-temperature space; and a light projecting means that faces the light projecting means and receives the laser light and converts it into electricity. The light receiving means and the rising output voltage of the light receiving means are compared with a first reference voltage for determining the presence of an article when the article is present and with a second reference voltage for determining the presence of the article when the article is absent. A rise determination circuit; a fall determination circuit that detects a change from article presence to article absence when the measured value of the falling time of the output voltage of the light receiving means becomes longer than a reference value; and a fall determination circuit that detects a change from article presence to article absence; A change in is determined only by the output of the rise determination circuit, and a change from the presence of an article to no article is determined by the establishment of both the rise determination circuit and the fall determination circuit, and a hysteresis characteristic is provided to determine the presence or absence of an article to the outside. An article detection device in a high temperature space, comprising an output control circuit that outputs a signal.