1. INSTALL THE SOFTWARE FIRST The software installs the necessary drivers for Microsoft Windows to recognize your National Instruments (NI) data acquisition device.
2. ACCELEROMETER TYPES SUPPORTED This software will work with IEPE single axis and triaxial (3-axis) accelerometers. IEPE accelerometers are also called ICP™, ISOTRON, CCLD, orDeltatron. These are names that vary by manufacturer, but they all mean the same thing: electronics are built into the accelerometer and a DC excitation current along the signal wire from 2mA to 20mA is required to power the accelerometer. Some instruments have the current excitation builtin, and others require an external device between the accelerometer and the instrument. This current powers theelectronics inside the accelerometer. The accelerometer should have a specification of “mV/g”.
3. MOUNTING THE SENSOR Proper sensor mounting is very important in reading the appropriate vibration signal. The best way possible is to drill a small hole into the device and screw the accelerometer onto the vibrating device. There are 2 common types of threading: ¼-28 and 10-32 threads. Smalleraccelerometers may not have built-in threads for screw mounting. In this case, using a little beeswax or a very small dab of cyanoacrylic (superglue) on the mounting surface will work. Finally – it’s important that the mounting is very clean and very flat. Special mounting options are available for mounting the sensor to a surface with a curvature. E-mail email@example.com if you need moreinformation about mounting options.
4. OPERATION OF SOFTWARE You can double click the “High-Speed Accelerometer Datalogger” link on your desktop or from Start Menu -> Programs -> JustMeasure. Once the software is launched, the next step is to set input parameters for the software to operate properly in this section:
“Channel” – This is a simple on/off switch toselect whether you’ll be saving data for that channel. “National Instr. Ch.” – This is an abbreviation for “National Instruments Channel” and represents the physical channel attached to the National Instruments hardware. For example – you may have 50 input channels connected to the NI Hardware and you want to switch the logging channels without reconnecting any cables on subsequent measurements. “MaxRecording” – This will stop the datalogging after a certain period of time, even if the “stop” button is not pressed. This application can create extremely large files, and this is a safeguard from that getting out of control. Additionally, it allows for you to stop without being in front of the software to press the “stop” button. The allowable range for “max recording” is 1 second to 600seconds (10 minutes). “Sampling Rate” – This is the sampling rate per channel for the data acquisition hardware. Options are available for 50,000 Samples / sec, 20,000 Samples / sec, 10,000 Samples / sec, 5,000 Samples / sec, 2,000 Samples/ sec, 1,000 Samples / sec, 500 Samples / sec, 200 Samples / sec, 100 Samples / sec, 50 Samples / sec, 20 Samples / sec, 10 Samples / sec HINT: You can get an errorif you set “sampling rate” for more than the data acquisition device can handle. Most devices divide their maximum sampling rate by the number of channels, so you can decrease the sampling rate or the number of active channels if you receive an error. HINT: Some data acquisition devices cannot sample at the exact rates available in the software options. The next lower sampling rate will be used,and the timestamp in the recorded data file will reflect this accurately. JustMeasure, LLC Page 2
“Max Expected” Input the maximum vibration levels you will need to measure in g’s. If you don’t know what kind of g force to expect, try a test run using the maximum range of the accelerometer you’ve chosen. You can do this by calculating what g force it would take to output 5 volts from the...