SAPHIR, Signal Physique et Intrumentation

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LabVIEW measurement noise and vibration to protect the environment from sites

The "SAVE" system uses tags sealed environments suited to construction sites.

Author (s):
Jean-Michel Chalons - Saphir
Henri Campagna - dB Vib Consulting

Industry (s):
Industrial control, materials (wood, steel, construction ...)

Product (s):
Data acquisition, dynamic signal acquisition, Modular Instruments, LabVIEW Sound and Vibration, E / S digital portable DAQ Toolkits

Objective:
Monitor levels of noise and vibration on construction sites to comply with existing regulations.

The solution:
Using NI LabVIEW modules with dynamic signal acquisition of the Series C, to develop a system (SAVE) Monitoring of noise and vibration generated.

Construction sites can generate noise and vibration that could "pollute" the environment. It exists in this area very precise rules, which sets limits not to exceed. That is why the ones to make sites that are imposing these regulatory and contractual environmental impact, need to have measurement systems simple and efficient, able to be integrated into a facility that often involves constraints.

To meet this need, companies Vib dB and Sapphire Consulting Partner Alliance National Instruments worked together to develop a system of acoustic and vibration called SAVE (for Monitoring Environmental Acoustics and Vibration), based on a modular architecture economic .

The regulations relating to noise
Decree No. 2006-1099 of 31 August 2006 on the fight against noise Neighborhood (evolution of the Decree of 18 April 1995), introduced in the Public Health Code, regulates the behavior of noise and noise from d ' activities (professional or sports activities, cultural or entertainment held in the usual way), and noise from construction sites. For each of these categories, the decree determines the criteria for determining whether a noise affect the tranquility of the neighborhood or to human health. The decree sets the limits on the emergence to 5 dB (A) during daytime (from 7 am to 22 pm) and 3 dB (A) at night (from 22 am to 7 pm), s values 'patch adds a term in dB (A), according to the cumulative duration of occurrence of particular noise. In addition, the regulation defines the concept of emergence, with the spectral values: 7 dB in the octave bands centered on standard 125 Hz and 250 Hz and 5 dB in the standard octave bands centered on 500 Hz, 1 000 Hz 2 000 Hz and 000 Hz 4

The regulations on vibrations
The vibratory aspect is mainly governed by the circular of 23 July 1986 relating to mechanical vibrations emitted into the environment by classified installations for environmental protection. The regulation sets the threshold of the spectrum of vibration does not exceed the activities of neighboring buildings, which ensures the integrity of surrounding buildings by type of construction (buildings, houses, group of buildings ...).

Depending on the situation and the criticality of the site, other constraints can be incorporated into the contract by the payer, such as the inclusion of vibration perception thresholds by man, or verification of the marked absence of tone.

To this are added the constraints inherent in the shipyard facilities. When making measurements in the external environment over relatively long periods (several months or years), the equipment must be sealed and the appropriate sensors.

A central server and client tags
SAVE is made up of several stations (clients) monitoring acoustic and vibration and a central server for monitoring. This provides a user interface to control data from the stations on the site.

Each station, or tag, is in the form of a sealed bag containing a laptop and hard equipment data acquisition, namely the acquisition modules 24-bit dynamic signal of the C series (9233 and NI NI 9234), interfaced to USB. Our choice was included in the NI-9234 module for its high dynamics, which makes it an ideal instrument for measuring noise and vibration, their integration and packaging IEPE for his guests.

The measurements are made through microphones, accelerometers or geophones exterior in overall levels or spectra 1 / 3 octave. The application allows you to attach to each track, the alarm and danger. When these thresholds are exceeded, relays are triggered via a digital output module high voltage NI 9481, to alert staff with light and sound alarms. The site managers and the environment can also be notified by e-mail automatically.

Wi-Fi to solve the wiring problems
A key component in a facility of this type is the wiring between sensor and transmitter, it is necessary to minimize to the issues of life of the installation and measurement quality. Difficult to envisage more than 100 meters between a sensor and transmitter, even with appropriate wiring. The passages of cables shall also be identified and protected to avoid damage.

Fortunately, there is the wireless technology. In this case, the tags can be removed using rather than a USB connection between the modules and the PC, but a liaison IEEE 802.11g (Wi-Fi). Simply use a medium-NI WLS-9163 module for the NI 9234. The wireless architecture provides maximum flexibility and allows an extension of the economic system.

In the same spirit, the communication between the tags and the supervision PC may not be performed using an Ethernet cable. We too are considering wireless technology.

Archived data, reread shared ...
When tags are placed on a site, the supervisor detects, configures and runs automatically. It downloads, displays and archive data and alarms installed tags. Remotely accessible, such data may be shared between multiple users. Saved in. WAV, they can be replayed to identify the origin of an overflow and lead to delayed treatment.

SAVE was developed under LabVIEW using the library NI Sound and Vibration Measurement Suite, which allows for easy analysis functions in accordance with international standards. In this case, the system measures the acoustic and vibration according to the standards NF-S-31010, IEC 61260, IEC 61672, IEC 1260 and ISO 2631.

Other applications for SAVE
The functions of monitoring, archiving and making decisions (tripping relay) in the system make SAVE-Vib dB (www.dbvib.com) was able to adapt the product to other applications. We can cite as an example of a monitoring group turbo alternator at EDF, monitoring piping in SFM or acoustic control system at the end of assembly line in adduxit.

September 2008

Author information:

Jean-Michel Chalons
Saphir
Rue du Mail
Barraux 38530
France
Tel: +33 4 38 92 15 50
jmc@saphir.fr

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