This results in high demands on the scanning accuracy and dynamic range of measuring instruments. AdLINK realize noise detecting PCI-9846 equips the high-speed digitizer with a driver for LabVIEW. After installing the DAQPilot driver, the toolkit of daqpilot in the LabVIEW is available database. This tool provides control functions for data acquisition. The control functions and invocation methods correspond to the driver software DAQmax national instruments and are therefore comfortable to use.
For example the four elements are shown in the following figure (PLT create virtual channel, PLT PLT clear task, timing and PLT read) a complete function for continuous data collection. In addition the Toolkit DAQPilot provides also examples of LabVIEW with functions such as input and output of analog and digital signals. From these examples developer can learn quickly the required competencies. Figure 1: Continuous data acquisition with the high-speed digitizer PCI-9846 the signal acquisition module that forms the basis for the test system for acoustic emission testing, developed in this document, is based on the sampling procedure in Figure 1. After both the input channel, the gain of the preamp, filter and other parameters have been set, the user can start the continuous recording of data.
After the original signal is reduced by the magnification factor and digital filtering, has undergone noise and unnecessary frequency bands are removed. The continuous filtered signal can be stored in binary format or as text. Figure 2 shows the sound emission signal of the bearing that has been captured in the operation. The sampling rate of 2 MS/s, the filter is a 4th-order Butterworth lowpass and the cut-off frequency is continuously at 50 kHz. Figure 2: captured sound emission signal parameter analysis of a noise after filtering will transmit continuously collected on an amplitude detector. Depending on the defined threshold of the amplitude and the set amount of time the waveform data of sudden onset noise intercepted from the continuously recorded signal.