High-Speed Distributed DAQ System for Bridge Structural Health Monitoring
The bridge health status monitoring is vital and indispensable to ensure the bridge safety and durability. The bridge vibration caused by the traffic, wind, earthquakes, or nearby machines will pose a grave threat to the bridge. If the vibration wave pattern happens to be the natural vibration mode of the bridge, the energy will continue to accumulate and cannot be dissipated. In the end, it will lead to a serious damage to the bridge. In this case, Advantech's distributed data acquisition system is adopted and provides a rugged and reliable solution for bridge health monitoring.
There are various models from the vibration waveforms of the object. By monitoring the vibration signals from the bridge and creating the models, we can compare the displacement of the waveforms in order to know the health condition of the bridge. In addition to the fragile parts of the bridge, a total of 32 accelerometers have to be installed at every interval of the bridge for monitoring, and it requires to use IEPE accelerometers for measuring. Because the sensors should be able to installed across the bridge for hundreds of meters, the ideal deployment will be placing the data acquisition and computing system onsite as well to minimize the cable length for sensors and to cut down the data transmission amount and the backend server loading. As the accelerometers and the data acquisition devices have to be installed in the outdoor environment so the system has to be withstand the weather and humidity. The client uses Python for software and algorithm development, so they need to collect data from DAQ module via Python API directly.
Advantech's AMAX-5580 EtherCAT edge controller with iDAQ-964 modular DAQ chassis and iDAQ-801 vibration acquisition module realizes real-time and distributed monitoring of accelerometer signals. Generally, the vibration frequency of the bridge is below 1kHz, the sampling rate of iDAQ-801 is 256kS/s with the sampling resolution of 24 bits, providing extremely high frequency analysis in frequency domain analysis. The module has built-in anti-aliasing filter to avoid distortion caused by accelerometers’ sensing frequency higher or close to the sampling frequency, which may cause misjudgment in frequency domain analysis. The AMAX-5580 EtherCAT controller is used to process and analyze the data, and it can also provide a connection with up to 100 meters between DAQ nodes, allowing for a large scale measurement scenario and remote monitoring requirements. Moreover, the iDAQ modular system also features wide temperature design to withstand the operating temperature range of -20 °C to 60 °C, and the aluminum alloy casing chassis can resist electromagnetic interference in the environment, ideal for outdoor application. We also provide the DAQNavi software development kit which supports multiple programming languages for any development needs. In this project, the client uses Python to develop their algorithm and software which can collect the data through our DAQNavi Python API from our iDAQ modules.
- AMAX-5580: EtherCAT Edge Controller
- iDAQ-964: 4-slot iDAQ Chassis for AMAX-5580
- iDAQ-801: 8-ch, 256kS/s/ch IEPE DSA iDAQ Module
- DAQNavi/SDK: Software development kit
In this case, the A/D high-speed data acquisition, multi-channel simultaneous acquisition, and integrated acquisition devices are the three major elements for realizing this application. Advantech’s solution from IEPE power supply, high-speed signal acquisition to a high-efficiency computer computing platform (AMAX-5580) and the software development kit (DAQNavi) all play an important role for realizing bridge health monitoring. More importantly, the iDAQ-801 software development program can be completed via the DAQNavi APIs. By using the APIs for development, the existing algorithm can also be implemented seamlessly. This decreases development time, and also the management cost afterwards.