DAQSYS Soluções Integradas

::: Description :::

In order to automate the operations of measuring acoustic noise levels (pressure and sound power) of home appliances and the like in reverberant chambers, DAQSYS - Data & Control has developed a system using National Instruments hardware and LabVIEW based software.

The system was developed according to stantards like, NBR 13910, IEC 60704, ISO 3743, and ISO 8960.

The system automatically performs steps of product stabilization that will be measured, performs the storing the measurements results in the database and automatically generates reports in MS Word or Excel.

The system operation is quite simple so that it is not necessary the presence of an expert in measurement. As several precautions must be taken before each measurement and various procedures must be followed, the measurement and control system can be automated so you can have more reliable results and no need of an expert full time available.

According to the regulations, the measurement of pressure and sound power of the products should be carried out when they have been previously softened and are in steady operation. The system allows configuration of the type of product to be tested so that the minimum characteristics of softening and stabilization are observed before the test starts. While the system is automatic and is implemented according to standards, ensuring compliance testing is far greater because the system will only perform measurements when stabilization is reached.

The procedure of measuring the sound power level is achieved by comparison, the measurement of a calibrated sound source reference and a known sound power output is needed. For this reason, the system requires the standard sound source to be measured in certain time intervals, so that these reference values are used to calculate the sound power level. If the operator does not carry out these standard measurements at scheduled times, or the measurement of this standard is different from the expected values in at least one frequency range, the system hangs and does not allow more measurements of products to be completed until the problem is solved.

::: Characteristics :::

Queueing of  “x” products softening and stabilizing outside of the reverberation chamber (through the serial numbers obtained by reading bar codes);

Automatic voltage and frequency selection for each registered product;

Measurements of internal and external temperatures, and electrical quantities, with storage in the database;

Independent control of the softening and stabilization of scheduled products;

Storage of important data acquired during the process of softening and stabilization;

Process report generation;

Flagging of “stabilized product” to release it for measurements in the reverberation chamber;

With the product within the chamber, the stabilization data are searched in the database,  and then the measurements will be performed automatically;

The acoustic measurements are performed according to standards. Fridges measurements for instance, must be carried out in at least three compressor operation cycles and should start one minute after the compressor starts, and be stopped one minute before it stops The measurements timing required to follow these are achieved in stabilizing routines, which are stored in the database;

Similarly, the temperatures and electrical measurement done outside the chamber, are monitored and stored in the database;

After measurement completion, the system automatically generates reports and releases the camera for new measurements (all test results are stored in the database).