Seismic measuring cases for CETE de l'ouest

Seismic measuring cases for CETE de l'ouest

Our objective :

To develop stand-alone systems able to collect data relating to vibrations emitted into the environment (public works sites, quarries, road traffic, etc.).  For safety reasons and simple usage, access to parameters and measurements must be available remotely.  The systems must be configurable from a vehicle close to the construction site.  In addition, they must automatically transmit the acquired data to a remote office.

The solution :

To integrate two CompactRIO chassis into small, waterproof cases for easy handling and transportation.  Supervisory control is assured by VASCO software, developed by NERYS on National Instruments LabVIEW 8.6.  The LabVIEW Real-Time and LabVIEW FPGA Modules are software add-ons used for the acquisition and recording functions, embedded on CompactRIO.  In addition, a GSM CompactRIO module and a router are used to transfer data to the supervisor or to a remote computer.

Centres d'Études Techniques de l’équipement, CETE de L’ouest is a public research and development, innovation and engineering organisation.

The LRPC, Laboratoire Régional des Ponts et Chaussées (Central Laboratory of Bridges and Highways), located in St-Brieuc, is involved particularly in the following areas :

- Natural risks

- Road safety

- Construction

- Road infrastructures

- Engineering work structures

- Geotechnics

As part of field testing, CETE key stakeholders measure the impact of the civil engineering works on the structures and infrastructures surrounding the site.  They carry out vibration measurements, synchronous and triggered, on about thirty track lanes equipped with geophone-type sensors.

The systems are used on construction sites and can be several tens of meters apart.  Therefore, it is imperative that the whole system be integrated :  weather, shock, dust and temperature variation resistant.

Existing solutions with little feedback

Currently there are measuring systems cases and recording instruments available.  These solutions have some major shortcomings :

- Integration not very ergonomic

- Airtightness and Watertightness do not meeting Ingress Protection Rating standards

- Communication of data during recording is not possible

- Software is either not or very little configurable

This leads to data loss, a waste of time and, in some cases, property damage.  In terms of upgradability, these solutions remain very limited, as well.

NERYS integrates measurement systems in any type of environment and uses regularly the CompactRIO to create stand-alone recorder solutions.  In terms of operating temperatures, resistance to shock and vibrations, minimal space requirement, weight and reduced consumption  this equipment an ideal choice for this type of application.

VASCO, test software designed by NERYS, has evolved rapidly and ensures full compatibility with all CompactRIO platforms.  This has been made possible by the use of LabVIEW FPGA development modules and the optimization of LabVIEW Real-Time developments that had already been carried out on real-time PXI platforms.

Waterproof, autonomous and remotely configurable cases

We have selected two eight-slot CompactRIO chassis, seven 9239 type synchronous analog input modules, one GPS CompactRIO module, and one Wifi router module.

Each chassis is integrated in a waterproof technical case.  The connectors are also waterproof and allow the geophone sensors to be connected directly without having to open the case.

The cases are linked together for synchronisation and data transfer.

The case which records all of the data is called a master case.  A Wifi interface allows a user to take control of the system from a laptop PC in a vehicle.  It can be configured and the data visualized in real time from the VASCO supervision module.  This makes it possible to check that all the sensors are operational and working correctly.

Once the shooting campaign begins, access to the site is impossible.  As the tests are destructive, the real-time aspect and the recording of data on events allow CETE to recover 100% of the data.

During long-term testing, the data is sent to a desktop computer, located on the CETE premises in Saint Brieuc, via a GSM link.

The processing software developed by the CETE was converted in LabVIEW 8.6 and allows to replay and format the recorded data in VASCO format.

The choice of CompactRIO chassis and the solution for integration offer great flexibility during usage and allow CETE to carry out very precise field measurements in all weather conditions.

Evolution of the system :

The main evolutions which will be brought to the measuring cases are :

- An increase in the number of channels: one of the two chassis still has CompactRIO slots available.  If necessary, it is possible to add on additional slave cases to increase the number of measuring points.

- Wireless synchronization : Currently, synchronization is wired via the trigger input of the CompactRIO.  Another evolution would be to equip each slave case with a GPS module for CompactRIO and to use IRIG-B signals for the synchronization of the recordings.

- Autonomy: Presently, the cases are powered by an external power source.  NERYS is working on the integration of rechargeable batteries with the possibility to use renewable energies such as solar panels or mini wind turbines.

Geothermal on-site supervision

In association with AMCPI, its Bordeaux partner, NERYS has just delivered a complete turnkey solution for the supervision of geothermal energy for GAZ de Bordeaux.

By using VASCO software (Visualize Acquire Supervisor and Control), NERYS was able to propose a quick solution to retrieve all of the supervision data and to control the different valves and pumps. The application runs 24 hours a day, 7 days a week, with the possibility of remote control via an internet explorer.  In addition, when thresholds exceed on certain values, maintenance managers are notified by a text message or a voice server call.  This supervision enables hot water to be supplied to various municipal buildings, including the Judaica swimming pool in Bordeaux.  

AMCPI is responsible for the installation, cabling, project management as well as on-site adjustments.  With this kind of application it is a big plus to have a relay on site just in case there is an evolution and for an efficient after-sales service.