Simultaneous Collection of Current and Vibration Data

The information provided is for help with Commtest Instruments products:

vb3000 instrument

QUESTION

How can I configure my vb3000 instrument to take simultaneous time waveforms of both vibration and electrical current?

ANSWER

Set up the vb3000 instrument to capture time waveform acceleration on both channels (measurements must be taken in acceleration so that the signal is captured without integration).

Setup

From the Main Menu press [1] then [0] to display the Set Parameters Menu.
Press [9] Sensor then set the sensitivity as usual for the accelerometer.
For the current sensor you need to tell the instrument that it is an accelerometer! This is because you want simultaneous vibration and current readings, and the instrument requires both channels to have the same recording type. For a typical 10 mV/A clamp-on current probe set the sensitivity to 10 mV/g.
In this same menu make certain that drive current is OFF.
Press [ENTER] to return to the Set Parameters Menu then press [3] and Set the Fmax value low enough to have a meaningful time sample in the frequency of interest (we recommend setting the Fmax to 100 Hz).
Press [ENTER] to return to the Set Parameters Menu then press [5] No of Averages.
Press [1] and set the number of Averages to 1.
Press [ENTER] to return to the Set Parameters Menu. Ensure that Time mode is selected then press [2] and set the number of samples to get a meaningful time sampling. (At 8192 samples the data capture will take 32 seconds.)
Start data collection as normal by pressing [START/STOP].
After the specified time (32 seconds in this example) a waveform will appear in the display. Press [START/STOP] immediately to freeze the data capture for storing. (Press [8] to toggle between displaying CH1 and CH2 data.)
Press [MENU] to store the channels and save them to the appropriate machine locations.
Upload your data to the Ascent software for in-depth analysis. Current recordings will be scaled as 1 g = 1 A.

Note:

For normal current measurements the sensor need not be configured as an accelerometer but instead as a current sensor as outlined in your vbSeries Instrument Reference Guide. (Normal current readings are taken without collecting vibration data at the same time.) Further information on taking current readings can be found in the following FAQ: Current Readings with the vb Instrument.

FAQ ID: 17421 Last Reviewed: 3 April 2006