AN43: Remote relay and water leak detection with HWg-WLD

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HWg-WLD – LAN water flood detector can detect water leaks but does not directly feature relay outputs. This Application Note shows how to signal leaks using remote relay outputs (Damocles 1208).

  • Four HWg-WLD water leak detectors are placed at various locations in a building.
  • Some of them are powered over the Ethernet (PoE) using CAT5 cable.
  • The Damocles 1208 unit is located anywhere in the building where flood needs to be signaled.
  • All four HWg-WLD water flood detectors are monitored over SNMP independently of the relay outputs.

HWg-WLD configuration

  • In the HWg-WLD web interface, select a “Damocles” remote device.
  • The “Remote ID” value is the output to be activated.
    Use 150 + output number = e.g. "152" to control Digital Output 2.
  • Each HWg-WLD detector must control a different output.

  • Username and Password must allow write access to the remote device.
  • Remote outputs are controlled using XML.
  • The remote output is set every time the status of the sensing cable changes, and periodically updated every 10s in order to recover after remote device power failures.

    Damocles configuration

    • To control O1, set Remote ID = 151 at the source device.
    • The output must be configured in manual mode.


    Technical notes

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    • Is it necessary to keep some software running in order to control relays over IP?
      No, remote relay control works in the Box-2-Box mode, no software is needed.
      Any Poseidon or Damocles product can be used as the remote relay output. HWg-WLD periodically (10s) sets the state of the selected output using XML.
    • When is the water leak alert sent to the remote relay? Only upon activation?
      No, this is a robust system. Box-2-Box mode updates the information periodically (every 10s by default).
    • Can I connect several HWg-WLD to the same Damocles unit with relay outputs? Yes, but please use only one HWg-WLD per Digital Output (DO). Thus, in a typical application, 8 HWg-WLD units are linked with one Damocles 1208 unit with 8 DO. Each output signals a water leak at one particular zone.