3 Wire DC

The provided information describes 3-wire DC proximity switches, which are commonly used in industrial automation for detecting the presence or absence of objects without physical contact. Below is a structured breakdown of the key details:

Typical Applications

  • Industrial Automation: Object detection in conveyor systems, robotic arms.

  • Logic Circuits: Interfacing with PLCs, counters, or microcontrollers.

  • Relay/Solenoid Control: Directly driving small DC loads (<300mA).

  • High-Speed Counting: Suitable for applications requiring 1kHz switching frequency.

Selection Considerations

  1. Choose PNP for PLCs with sinking inputs.

  2. Choose NPN for PLCs with sourcing inputs.

  3. Ensure the load current does not exceed 300mA.

  4. For harsh environments, verify IP68 compatibility.

Key Features of 3-Wire DC Proximity Switches

  1. Operating Principle:

    • Function as inductive or capacitive proximity sensors (depending on type).

    • Detect metallic/non-metallic objects within a specified range (1mm–50mm).

  2. Output Types:

    • PNP (Sourcing):

      • Output provides +Ve voltage when active.

      • Load must be connected between output and ground (-Ve).

    • NPN (Sinking):

      • Output sinks current to ground when active.

      • Load must be connected between output and +Ve supply.

  3. Electrical Specifications:

    • Voltage Range: 10–30V DC.

    • Current Consumption: <10mA at 30V DC.

    • Switching Current: Max 300mA (suitable for relays, PLCs, or small solenoids).

    • Switching Frequency: Up to 1 kHz (fast response for high-speed applications).

  4. Protections & Safety:

    • Short-circuit protection: Prevents damage if output is accidentally shorted.

    • Reverse polarity protection: Safeguards against incorrect power supply connection.

    • Inductive spike suppression: Protects against voltage spikes from inductive loads (e.g., relays).

  5. Mechanical & Environmental:

    • Housing Material: Chrome-plated brass (durable and corrosion-resistant).

    • IP Rating: IP68 (dust-tight and submersible in water).

    • Mounting Options: Flush or non-flush (depends on sensing requirements).

  6. Performance Metrics:

    • Hysteresis: 5–10% of sensing distance (reduces false triggering).

    • Repeatability: 5–10% of sensing distance (consistent detection).

    • Status Indicator: LED for visual feedback.

  7. Cable & Customization:

    • Standard cable: 3-core, 2 meters (can be customized for length or connector type).