《光電開關(guān)檢測技術(shù)》PPT課件

Emitting methodPulse-modulated Most of the photoelectric sensors emit a beam which is pulse-modulated. In this method, a strong optical signal of fixed width is emitted at a fixed time interval. This helps the receiver to distinguish the signal from extraneous light and to achieve a long sensing range. Unmodulated The high-speed fiber sensor FX2-A3R and the color mark sensor LX-12N series use an unmodulated beam.In this method, the beam is emitted constantly at a fixed intensity.This enables high-speed response, although the sensors are a little susceptible to extraneous light as compared to the sensors using a modulated beam. 引 起 理 想漫 反 射 的光 度 分 布 局 部 較 強(qiáng) 漫反 射 時(shí) 的 光度 分 布 Opposite types of polarizing filters are placed in front of the emitting and receiving elements. A horizontal polarizing filter placed in front of the emitting element passes only horizontally polarized light and a vertical polarizing filter placed in front of the receiver ensures that only vertically polarized light is received.Using this configuration, even specular objects can be reliably detected. 1 Normal unpolarized beam emitted from the LED oscillates in a random manner. As it passes through the horizontal polarizing filter, the oscillation is aligned horizontally and the beam is horizontally polarized.2 When the polarized beam falls on the reflector, its polarization is destroyed and the reflected beam oscillates in a random manner. So, the reflected beam can pass through the vertical polarizing filter and reach the receiving element. However, a specular object does not destroy the polarization. The reflected beam oscillates horizontally, as before, and cannot pass through the vertical polarizing filter. 光 纖 傳 感 器 When light is incident on the core, it propagates in the core by being totally reflected at the boundary between the core and the cladding. After traveling through the fiber, light spreads at an angle of approx. 60 at the cable end and is directed on the sensing object. Fiber sensors are classified broadly into two groups thru beam type and reflective type. The thru-beam type has two fiber cables: the emitting cable and the receiving cable. The reflective type has one fiber cable that contains, both, the emitting part and the receiving part. 三線式 二線式 1.紅 外 線 光 電 開 關(guān) 在 環(huán) 境 照 度 高 的 情 況 下 能 穩(wěn)定 工 作 ， 但 原 則 上 應(yīng) 回 避 將 傳 感 器 光 軸 正 對太 陽 光 等 強(qiáng) 光 源 。2. 當(dāng) 使 用 感 性 負(fù) 載 （ 如 燈 、 電 動(dòng) 機(jī) 等 ） 時(shí) ，其 瞬 態(tài) 沖 擊 電 流 較 大 ， 可 能 劣 化 或 損 壞 交 流二 線 的 光 電 開 關(guān) ， 在 這 種 情 況 下 ， 請 經(jīng) 過 交流 繼 電 器 作 為 負(fù) 載 來 轉(zhuǎn) 換 使 用 。3. 紅 外 線 光 電 開 關(guān) 的 透 鏡 可 用 擦 鏡 紙 擦 拭 ， 禁用 稀 釋 溶 劑 等 化 學(xué) 品 ， 以 免 永 久 損 壞 塑 料 鏡 。 材 料 邊 的 控 制 倉 庫 門 警 衛(wèi) 高 度 辨 別 氣 流 量 的 監(jiān) 測 沖 壓 床 安 全 監(jiān) 視 自 動(dòng) 注 料 物 體 倒 置 辨 別 料 位 控 制 進(jìn) 出 檢 測 不 合 格 的 檢 出 物 體 前 后 控 制 煙 霧 檢 測 圍 墻 警 戒 轉(zhuǎn) 速 檢 測 斷 裂 檢 測 直 徑 限 制 定 位 剪 切 電 動(dòng) 扶 梯 自 動(dòng) 啟 停