SigDAQ

SigDAQ is the Data Analysis software package available for use with the Keynes Controls range of ATM network based data acquisition products. The software enables data from any channel of any SONET node connected to an ATM network to be analysed. The data analysis allows for time domain traces as well as Spectral analysis to be carried out. SigDAQ must be used in collaboration of a suitable ATM network interface card within the data logging computer.

SigDAQ enables time domain traces to 2048 points per channel to be plotted and power spectrums to 1024 lines per channel to be calculated and displayed. Simple channel statistics can be overlaid on any of the traces be they time domain or frequency domain. The spectral analysis allows for different Radix-2 FFT sizes, Windows functions and ensemble averaging to observed in real time.

Within SigDAQ There are no software limitation to the number of channels that can be analysed and plotted. The only practical limitation to the software is the ability of the data analysis PC to undertake specified operations. Keynes Controls recommends that only high performance modern PCs operate this advanced software. All of the data plots are fully User Configrurable.

The SigDAQ software interrogates the ATM data acquisition system configuration files for set-up information and automatically prepares a list of available instruments. This list is used by the operator to choose the nodes/channels to be interrogated. Each instrument is individually configured at the time of manufacture to ensure that it's information cannot be mis-identified under analysis. As long as the instruments have been correctly configured then there data will appear in the SigDAQ software.

The SigDAQ software utilises the driver software configuration files to obtain the list of SONET nodes within the data acquisition instruments, and therefor channels being used to acquire analogue input data. The ATM network can be in fact any suitably defined standard network utilising any suppliers hardware. There are no proprietary standard and protocols used for the acquisition and transmission of data.

It does not matter how or what route the ATM data from the SONET nodes built into the Keynes Controls instruments arrives at the data logger PC. It can be via a standard ATM switch, directly using copper or fibre optic networks or by microwave data link. In fact any combination of the above so long as the data contains the ATM packets protocol.

Any combination of Keynes Controls ATM products can be combined on an ATM network. The SeaDAQ instruments can be deployed underwater and the rack systems solutions at other dry locations yet all information remains synchronised and can be analysed within this software.

In order to maximise the number of channels that can be analysed, the spectrum calculations are restricted to a maximum FFT size of 1024 points. To maintain the timing within the traces there is no overlapping of the input data within the Window functions. A user must utilise the Hamming or Hanning Windows and ensemble averaging to enhance the signal noise ratio's of the input data and to extract peaks from within noise.

Figure 1 shows an example of a single channel time domain trace from the SigDAQ software. All aspects of the trace configuration are user definable. Multiple channels, screen size, labels, axis configurations and titles can all be setup for a specific event. The standard Windows features such as Save to Clipboard, Save Trace to File and Print Trace are all available as screen icons.

Each channel to be plotted can be selected using the Node/Channel Onbutton and all chosen channels are displayed on a single trace. Multiple traces can be setup allowing a User to easily group channels of interest. It is even possible to plot the same channel a number of times using different scaling and channel combinations. In order to ensure seamless scrolling of data the number of data points per channel plotted is restricted to 2048.

The SigDAQ spectral analysis operations enables an operator to observe the input data as a series of Fourier Transform power spectra. The maximum size power spectra is currently 1024 points per channel. In order to optimise the sidelobe surpression and separate peaks a number of Windows functions are provided such as Hamming, Hanning and Rectangle.

The spectral configuration supports 2 different modes operations Free Running and Ensemble Averaging. The Free Running mode updates the spectral plots each time a new spectra is calculated and shows a fast response to signal changes and characteristics. The Ensemble averaging mode effectively slows down the spectral updates and can be used to improve S/N ratios. It is also easier to take measurements using the cursor controls when the spectra changes very slowly. The Ensemble averaged spectra will only update after the preset number of spectra are calculated.

The spectral analysis plots can be fully User defined and support all of the same configuration tools described for the time domain plots shown in Figure 1. Each new plot is activated by selecting the button. Once a new chart appears on the screen then selecting the Nodes/Channels On menu adds new spectra for the specified input to the trace. Simple chart statistics can be observed for each trace.

Once a Spectra has been setup then traces can be easily printed to file or to a local printer for later comparison. All the standard Windows operating system features for graphics are maintained enabling traces to be copied and pasted directly into reports.

Just like the time domain plots multiple channel spectra can be overlaid as shown in Figure 2. This example only shows two channels power spectra. In practice more channels can be included in a single plot. The power spectra calculations are sensitive enough to observe the DC offset of the input channels. The DC error can be calibrated out within the channel configuration settings.

Figure 3 shows a typical layout of the main screen for the SigDAQ Analysis software. In order to keep the example simple only 2 channels are shown overdrawn on the plots however the data for each channel is from a separate instrument.

There is no physical restrictions within the software to the number of traces that can be setup. In practice care should be taken to restrict the number of large point spectral plots. The number of plots that can be configured will depend on the performance of the data analysis PC. A fast computer can process more spectra than a slow one. More traces can be setup than can be sensibly shown at any one time on the screen, these additional traces can be sent to the background and called for examination with a few simple key clicks or using the mouse pointer. The screen can get rather cluttered when many channels are open but sending unwanted traces to the background can be advantageous.

Each of the plots are formed in separate Windows and can be scaled or compressed like any other Windows applications. Even though Fig 3 shows the spectral plots at the top of the screen they can in fact be placed anywhere. A number of screen configuration buttons are available that can be used to automatically scale and layout the plots.

The SigDAQ software cannot be used to reconfigure the instruments and its sole purpose to analyse the incoming data. When used in collaboration with the configuration software it is possible to adjust the timing setup parameters for specific instruments in order to calibrate out or reduce the effect of the propagation delays caused by the network links. When an instrument is set into Calibration mode then the calibration signals can be observed and the results tested against software calibration factors.