Fiber optic through-beam sensors use separate emitter and receiver fiber heads connected to an amplifier, allowing detection in tight or harsh environments while keeping the electronics remote.

Basic Components and Wiring

A fiber optic through-beam sensor consists of three main components:

1. Fiber Amplifier Unit – Contains the light source, signal processing electronics, and output circuitry.
2. Emitter Fiber Head – Transmits light from the amplifier to the target area.
3. Receiver Fiber Head – Collects the transmitted light and sends the signal back to the amplifier for detection. Wiring Steps:

• Connect the amplifier unit to the power supply according to the manufacturer's specifications (typically 12–24 VDC).
• Attach the emitter fiber to the amplifier's output port and the receiver fiber to the input port.
• Route the fiber cables to the sensing location, ensuring they are not bent beyond the minimum bend radius to avoid signal loss.
• Align the emitter and receiver fibers so that the light beam passes directly from the emitter to the receiver.
• Connect the amplifier's output terminals to the control system (PLC, relay, or other devices) to receive the detection signal.

Installation Considerations

• Tight Spaces: Fiber heads can be installed in confined areas where the amplifier cannot fit, making them ideal for compact machinery or narrow detection points ( ).
• Harsh Environments: Since the fiber heads contain no electronics, they are resistant to heat, water, vibration, and electrical noise ( ).
• Alignment: Use visible light fiber heads if possible to simplify alignment. The beam should be unobstructed for accurate detection.
• Aperture Selection: For small parts, select fiber heads with smaller apertures to improve detection precision. If the target is very small and the span distance is large, you may combine a standard aperture fiber on one side with a smaller aperture fiber on the other to maintain range and accuracy ( ).

Operational Tips

• Ensure the amplifier is mounted in a location with easy access for adjustments and maintenance.
• Avoid sharp bends or kinks in the fiber cables to prevent signal attenuation.
• Test the sensor with the actual target to verify detection reliability and adjust the amplifier sensitivity as needed.
• For long-range detection, consider high-output fiber amplifiers or fibers with larger apertures to maximize received light intensity ( ). By following these wiring and installation guidelines, fiber optic through-beam sensors can provide fast, non-contact detection in challenging industrial environments while keeping the sensitive electronics safely away from the sensing point.