The **FTG-20-R** is a specific model of a **Fork-type Photoelectric Sensor** (often referred to as a "Slot Sensor" or "U-frame Sensor") typically manufactured by companies like **RIKO**. These sensors are widely used in industrial automation for detecting the presence of objects passing through the slot. --- ### 1. Technical Specifications The "FTG" series generally follows a standard electronic profile suitable for PLC (Programmable Logic Controller) integration. | Feature | Specification (Typical) | | :--- | :--- | | **Sensing Distance** | 20mm (Width of the fork/slot) | | **Operating Voltage** | 12 - 24V DC | | **Output Type** | NPN or PNP (Model dependent, usually Open Collector) | | **Output State** | Selectable Light-ON / Dark-ON | | **Response Time** | < 1ms | | **Indicator** | Red LED (Operation indicator) | | **Connection** | 2M Cable or M8 Connector | --- ### 2. Internal Electronic Components The device operates on an infrared optical pair system. Its electronic architecture consists of three main stages: #### A. The Emitter (Transmitter) * **Infrared LED:** Emits a beam of modulated light across the 20mm gap. * **Oscillator Circuit:** Pulses the LED at a high frequency to distinguish the sensor's light from ambient light (preventing interference). #### B. The Receiver * **Phototransistor/Photodiode:** Located on the opposite arm of the fork. It converts incoming light into a small electrical current. * **Amplifier & Comparator:** Boosts the signal from the phototransistor and compares it against a threshold voltage to determine if the beam is "broken" or "clear." #### C. The Output Stage * **Switching Transistor:** Usually a power transistor (NPN or PNP) that acts as a switch for an external load. * **Protection Circuitry:** Includes reverse polarity protection and short-circuit protection to prevent damage from incorrect wiring. --- ### 3. Wiring Configuration Most FTG-20-R sensors follow the standard industrial color-coding: | Wire Color | Function | Description | | :--- | :--- | :--- | | **Brown** | +VCC | Positive power supply (12-24V) | | **Blue** | 0V / GND | Negative power supply | | **Black** | Output | Control signal sent to PLC/Relay | | **White** | Control/Mode | Often used to toggle between Light-ON and Dark-ON | --- ### 4. Key Applications * **Label Sensing:** Detecting gaps between labels on a roll. * **Positioning:** Detecting the edge of a metal or plastic plate. * **Counting:** High-speed counting of teeth on a gear or parts on a conveyor. * **Level Control:** Detecting the top of a container.