SC15 Product Description

The SC15 is a tool for measurement and analysis of vibrations and auxiliary voltage signals. The system is based on a laptop personal computer, two accelerometers and the SC15 amplifier module. The system converts the analog signals to digital data so you can view, compare and analyse waveforms and spectra.

The computer is programmed to function as a two channel spectrum analyser. The information is displayed graphically on the screen from which hard copies can be made on industry standard printers. Data can be exported to spreadsheet programs or modal analysis software for further processing.

The SC15 spectrum analyser - showing a waveform and the corresponding spectrum

The SC15 has a two channel amplifier with anti-aliasing filters. Each channel may be switched between a current source supply for an accelerometer and an auxiliary voltage input.

All the SC15 components fit neatly into a carrying case which is supplied. The complete system is powered from the laptop so that operation without a main power connection is possible.

SC15 Applications

Surveys
You can make accurate surveys of vibrations. For example, you may want to install a scanning electron microscope (SEM) in a location where there are many pieces of equipment and air handling units. You can use the SC15 system to survey the vibrations to make sure that they are within specification at the proposed site for the SEM. The industry standard 1/3 octave analysis feature is useful in this application.

The SC15 complements the SC11 Analysis System, which can perform a full site survey of magnetic fields, vibrations and acoustic levels, but has only a single channel spectrum analyser.

Trouble shooting
The accelerometers have very low noise, so they allow you to resolve low frequency vibrations (down to 0.1 Hz). The two channel spectrum analyser enables you to compare frequency components of vibrations at different locations in order to locate sources of vibration.

Analysis
You can directly compare the spectrum of vibrations on one channel with that of any voltage source on the other channel. For example, you can connect the auxiliary input to the video output of an SEM in spot mode to compare vibrations with the movement of the electron beam. This can help you to determine whether image distortions are due to vibrations.

You can use techniques such as hammer testing to measure the transfer function of vibration isolation systems and other structural components and export the data for modal analysis.

SC15 Hardware

Laptop computer
The laptop computer is optionally supplied by Spicer Consulting with all the software pre-installed. Alternatively you may install the software on your own laptop PC. If desired, Spicer Consulting can install the system on your own computer. The minimum requirement for the computer is a 266 MHz Pentium with 64 MB RAM, 100 MB free hard disc, CD-ROM, 3½in floppy disc drive and PCMCIA slot.

Accelerometer
The accelerometers supplied are the Wilcoxon Research model 731A, with a measurement range of 200 mg's pk-pk and a bandwidth of 0.1 Hz to 500 Hz in this system. The accelerometer is suitable for the measurement of extremely low level vibrations. The accelerometer measures along one independent axis.

The accelerometer can be rotated to measure three orthogonal axes while standing on a horizontal plane.

Customisation

The spectrum analyser can load and save the control settings to named files so that it can be quickly configured for standard measurements. User-defined units may be entered for use with other sensors connected to the voltage inputs.