Bridge Monitoring Systems

Bridge monitoring systems

Bridge Monitoring Systems

Distributed Monitoring Solutions or Bridge Monitoring Systems on Large Scale Constructions application note provided by our partner DEWESoft.

The DEWESoft® EtherCAT® (ECAT) solutions have already become standard in distributed, industrial monitoring applications. But when we are talking about monitoring the HongKong-Zhuhai-Macao Bridge, “distributed” becomes a whole new dimension…

Introduction on a Bridge Monitoring System

With a total length of 50 km, the Hong Kong-Zhuhai-Macao Bridge (HZMB) is regarded as the longest sea bridge in the world. One part of this monument’s structural health monitoring system is the measurement of tri-axial accelerometers at the navigation spans. The purpose is to detect the occurrence of the ships impacting as well as to determine the global dynamic characteristics of the structure’s viaduct bridges.


For the Hong Kong part of the HZMB, 200 highest precision acceleration channels are needed, distributed over several kilometres. These channels are clustered into six independent subsystems (DAU 1 .. DAU 6) as shown below.

The data of each DAU subsystem are stored locally and in parallel to a database engine running on a central server.

Main requirements:

  • Fully remote controlled system operation
  • Synchronisation accuracy between each DAU: better than 1 msec (10 µs within each DAU)
  • Aliasing free acquisition over complete sampling range (up to 10kS/sec)
  • ADC resolution ≥ 24Bit with 0.1 % basic accuracy.
  • Sensor must be supplied out of DAQ system (±15 Volt)


The performance of the Sirius EtherCAT® slice model: SIRIUSie-8xLV fits perfectly to the used sensor.

For the long distances between the slices to each DAU and the mixed network topology (daisy chain and star) the connection possibilities of our ECAT families was expanded:

  • The low latency EtherCAT® to Fibre optic converter (ADAPTER-OPTIC-ECAT) allows expansion of the distance over several kilometres.
  • Up to 8 EtherCAT® lines can be connected with a dedicated EtherCAT® hub (ECAT-HUB-8).

NTP-Sync is used for synchronisation between the DAU’s.


Feel safe when driving from Hong Kong to Macao or vice versa. This bridge is monitored with world’s most accurate distributed DAQ system: SIRIUS EtherCAT®.

Contact us to find out more information.