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  • Photoelectric sensor | through-beam type | for liquid detection | 6–13mm | 16×17.2×26mm | 10–30VDC | NO/NC | PNP | 2m cable | PBT | infrared | IP50

    Code: PU13S-TDPB

    The photoelectric liquid level sensor is a compact, reliable, and modern solution for monitoring liquid levels through transparent pipes, designed for both professional industrial applications and household or laboratory use.
    The sensor uses an infrared beam to detect the presence or absence of liquid inside the pipe without direct contact with the fluid. Thanks to its U-shaped design and PBT plastic housing, it is easy to install, durable, and resistant to vibrations.
    An indispensable device for automation, chemical, food, pharmaceutical, water treatment, and cooling systems, where reliable liquid level control is essential. 

  • Technical specifications
    Detection type: Through-beam
    For pipes: Outer diameter Ø6–13 mm, wall thickness ≤1.0 mm
    Light source: Infrared (940 nm)
    Output type: PNP, NO/NC (switchable via DIP switch)
    Response time: < 1 ms
    Supply voltage: 10…30 V DC
    Current consumption: ≤20 mA
    Load current: ≤100 mA
    Voltage drop: ≤2.5 V
    Protection: Reverse polarity protection
    Indicators: Red LED – output
    Light interference resistance: Sunlight or lamp light < 3000 lx
    Operating temperature: -10…+50 °C
    Humidity range: 35–85% RH
    Protection class: IP50
    Housing: PBT
    Connection: 2m PVC cable
    Dielectric strength: 500 V AC, 50/60 Hz, 60 s
    Insulation resistance: ≥50 MΩ (500 VDC)
    Vibration resistance: 1.5 mm amplitude, 10–50 Hz (2h each direction X/Y/Z)

    Functions and operating principle
    The sensor operates on a through-beam principle – infrared light passes through the pipe and reflects differently depending on whether liquid is present inside.
    The system quickly detects light changes and determines the presence or absence of liquid, activating the output signal.

    Use and applications
    For home users or DIY: Suitable for monitoring liquid levels in aquariums, humidifiers, or cooling systems.
    For engineers / automation specialists: Ideal for automated systems requiring fast and reliable liquid detection through pipes (e.g., dosing, filtering, or cooling lines).
    For electricians / technicians: Used in process control systems; can be integrated with PLCs, signal modules, or control relays.

    Advantages

    Arc-shaped design – easy and stable installation

    Fits transparent pipes of various diameters (Ø6–13 mm)

    Fast response time

    Resistant to vibration and ambient light

    Disadvantages

    Not suitable for opaque pipes

    IP50 protection – not resistant to direct water exposure 

    Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.
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