Remote, pole-mounted ‘SolarBox’ option provides essential power to low cost SV 307 for permanent noise monitoring using an integrated Class 1 sound level meter 

Reinforcing its position at the forefront of noise and vibration instrumentation for environmental and occupational health monitoring applications, Svantek UK has launched SolarBox, an all-in-one solar power system for use with its popular, low cost SV 307 Noise Monitoring Terminal.

The remote, pole mounted SolarBox provides essential power for Svantek’s small, lightweight SV 307 Noise Monitoring Terminal. The SV 307 has generated significant interest since its launch last summer which Svantek attributes to an extremely competitive price point and innovative Class 1 MEMs microphone with lifetime warranty.

The new SolarBox is a solar mount and enclosure in one neat unit, topped by a 110W DC-Solar 12V professional grade panel. It utilises monocrystalline SunPower cells offering quality, compact design and high outputs in low-light conditions. The built-in lead-acid battery helps ensure the system can run continuously, even in the worst of UK winters.

Protected by an IP66-rated waterproof, removable casing, Svantek’s SV 307 integrates a Class 1 (IEC 61672) sound level meter with 3G modem for fast data transfer over the internet to PC with standard connectivity. Offering optional airport and community characteristics, a Class 1 MEMs microphone enables wide frequency range up to 20 KHz with the measurement data stored on a microSD card.

The energy efficient NMT incorporates an innovative patented system check with an inbuilt reference sound source producing level of 100dB at 1 KHz. As an option, the SV 307 can perform real-time frequency analysis in 1/1 and 1/3 octave bands and save results with the time history data. In addition, it can record the audio signal as standard WAVE files for noise source recognition.

A large colour OLED display and 10 push buttons enable easy configuration of the NMT in the field removing the need for an external handset or reconnection to a PC.

The large windscreen is highly efficient in reduction of wind noise effects even at high wind speeds. Metal spikes protect the NMT from birds.

The SV 307’s waterproof casing can be easily mounted to a post and removed for quick access to the user interface. It also offers protection against extreme weather conditions whilst fulfilling Class 1 accuracy.

The SV 307 has an internal Li-Ion battery and interface for connecting the SolarBox. A waterproof mains adapter for charging the battery and powering the station is also included for continuous operation in the field.

Svantek’s SvanNET cloud service monitors the wireless communication, powering and access to the SV 307 data. The scope of the basic SvanNET can be extended with multipoint project management that offers data storage in the cloud, data sharing, advanced alarming and reporting features. SvanNET is an on-line solution which means it doesn’t require software installation and is accessible through a web browser. The responsive design enables use of SvanNET on various devices such as smartphones or tablets.

The SV 307 is available with a number of optional functions including an accurate GPS hardware module providing information on the localisation as well as measurement time synchronisation.

The SvanPC++ Environmental Measurements feature is designed for post processing of data recorded by the NMT. It offers a powerful calculator and an automated noise event finder for noise source identification.

The option for 1/3 octave real-time analysis allows measurement of the noise frequency contents and is used for verification of noise sources in the environment. Plus time domain signal recording to WAVE format works during measurement and is logged in parallel to a time history. Once downloaded to PC it can be played back. The SV 307 is supplied with a factory calibration certificate and 36-month warranty card.

We recently attended the 52^nd Human Response to Vibration Conference & Workshop at Cranfield University where Svantek Poland’s Marketing Manager, Jacek Kuczynski, gave a presentation on ‘The impact of contact force on the accuracy of hand-arm vibration measurement’.

https://www.cranfield.ac.uk/events/events-2017/52nd-uk-conference-on-human-response-to-vibration

Below is an abstract from a paper produced by Jacek and Piotr Kowalski Ph.D (Eng) from the Central Institute for Labour Protection in Warsaw which details a recent study into the use of hand-arm vibration adapters and the accuracy of hand-arm vibration measurements, in function of the contact force. The Institute performed 240 measurements where the impact of coupling force on vibration magnitudes was assessed using Svantek’s SV106 human vibration meters and SV105AF hand-arm adapters.

The two Svantek SV106 human vibration level meters meet ISO 8041:2005 requirements, and are designed to perform measurements in accordance with ISO 5349-1 and ISO 5349-2 standards, with special SV105AF hand-arm adapters mounted on handles of vibration exciters.

Abstract

Measurement of hand-arm vibration with the use of a hand mounted sensor ensures the most representative measurements, taken at the point of contact of hand with a vibrating tool.

When measuring vibration on a hand, simultaneous measurement of contact force verifies whether the force magnitude is sufficiently rigid. The contact force also provides information on operator’s work schedule and may help to instruct users if they are using excessive or too little force when working with hand-held tools.

Additionally, by knowing both the coupling force value and the vibration acceleration, it is possible to calculate actual vibration energy dose that has been transferred to a hand.

The results proved that measurements taken with hand-arm adaptors provide correct vibration results regardless of contact force changes and type of vibration signal. The study has also indicated that it is necessary to define a minimum force threshold in order to mitigate the uncertainty related to the contact between hand and a vibrating tool.

Conclusion

The study proved that the effect of changes of the force thresholds applied by the operator are irrelevant to the measured vibration acceleration values. This assumption is valid for the forces above threshold of 20 N, below which it is necessary to ensure the correct coupling between hand-arm adaptor and vibrating surface. Together with the force level drop below 20 N, the uncertainty related to the coupling increases rapidly. However it is necessary to note that in practise, for tools generating high vibration amplitudes, the threshold of 20 N may not guarantee the perfect coupling, therefore higher threshold levels should be established.

Summary

At the time the ISO 5349 standard was introduced it was practically impossible to perform force measurements together with tri-axial vibration measurements due to limitations in hardware.

At the moment very small force transducers can be fitted right next to the MEMS-technology-based vibration accelerometer in a form of hand-arm adaptor as specified by ISO 5349-2 and ISO 10819 standards. In comparison to the technique of mounting sensor on a tool, the use of contact force allows defining the actual vibration exposure, whereas mounting on a tool bears the uncertainty of including into tests the periods when there was no contact with the operator’s hand.

As it has been proven, the use of hand-arm adaptors provides the same accuracy of vibration amplitudes as in case of standard piezoelectric vibration sensors mounted on a tool, but additionally offers the advantage of the best possible location of the measurement point – exactly at the point of transmission of the vibration signal to the hand of an operator and provides information on the actual exposure to the vibration.

There are numerous noise sources in ports and waterways, including horns, whistles, signals, terminal operations, engines, construction and logistics. As well as ensuring compliance with environmental noise regulations, operators must minimise, mitigate or reduce noise from both essential processes and other sources.

As a result, monitoring the impact of sound levels on local communities can be a complex issue. Operators and contractors need to regularly monitor compliance with noise abatement procedures and regulatory requirements, plus investigate enquiries or complaints from members of the public.

An increasing number of port operators such as Felixstowe, Port of Tyne and Peterhead are choosing to install a permanent noise monitoring solution, which allows them to capture sound levels in real time and gain a better understanding of existing noise levels and also track changes over time.

Svantek’s SV200 outdoor noise monitoring station offers reliable, accurate and continuous operation in the harshest conditions. A fully integrated solution for unattended long or short-term noise monitoring applications, the weatherproof SV200 is small, lightweight and easy to install by a single person.

It has its own built-in web server that can continuously provide live, real time data, 24-hours a day, seven days a week, to a computer or hand held device. It will send an email or text message if the noise levels go above a pre-set limit and measures and stores results suitable for automatic reports and detailed information for advanced post processing analysis.

Standard measurement functionality includes multi-profile data logging, real time 1/1 and 1/3-octave logging, audio event recording and statistical analysis. Measuring capabilities can be extended with real time audio streaming and weather condition monitoring. All results are securely stored on the built-in 16GB microSD card.

The reference direction is user selectable in the instrument configuration and a highly efficient windscreen reduces noise, even at high wind speeds. It features special rain protection and weatherproof housing protects the SV200 noise monitoring station against extreme weather conditions while fulfilling IEC 61672 Class 1 accuracy.

Weather conditions have a significant influence on noise measurements so the SV200 is equipped with an interface for meteo sensors. With the optional SV205 weather station, the SV200 can measure wind speed, wind direction, temperature, humidity, ambient pressure and rain. Weather data is stored in parallel to the noise measurements.

Svantek’s SV200 features internal heating and rugged dual layer housing with natural airflow enabling it operate from -30°C up to +60°C and humidity up to 100% RH. It has a 2.45 Ah internal Li-Ion battery and interface for connecting solar panels. A waterproof mains adapter for charging the batter and powering the station is also included.

The SV200 features an ‘all-in-one’ design making it suitable for portable, mobile and permanent noise monitoring installations. This means it can also be moved from one location to another whilst still being able to provide information as often as required. A mounting tool for mast or stand is included in the standard package.