NDAQ24 data acquisition system software help pages

Warning: not up-to-date - some changes in the software are not descibed here

Measurement | Using excitations | Calibration | Impedance display | XY display | Signal display | Saving setups | Mouse and shortcut keys

User interface

The available functions can be accessed using the main menu, the toolbar buttons and via mouse and keyboard operations. Measured raw data and calculated data are displayed in the same window splitted according to the settings.

During measurement the display is refreshed ten times per second. Note that real-time display of many channels and longer duration may be a bit slower on older PCs. In such case choosing shorter display intervals (below 10 seconds) and lower sample rate (512 or below) can speed up operation.

Most of the display settings, measurement and analysis options are automatically saved upon exit and loaded upon starting of the application.

Measurement

The device should be powered and connected to the USB port before use. The USB connection may require a few (up to 10) seconds to be properly initialized, during this time the software can't communicate with the device

If the device is not present, simulation mode will be executed to do off-line work (setting up future measurements, importing excitation and calibration data, save setups, etc) or just to allow exploring of the features.

The Measurement menu has the following items:

• Start: starts the sampling process. Pressing space will also do this.
• Start in tracking mode: starts the sampling process in tracking mode, so only a single frequency will be used. The software asks the user to select excitation frequency then starts sampling. In this mode only impedance trend can be displayed. To measure impedance spectrum, use the alternative mode.
• Record: active during sampling and recording, will start recording for a specified duration (1-120 seconds can be selected in the options dialog box). Can also be activated by pressing space. Activating during recording will restart the recording process.
  When the recoring is complete, the software will prompt for a file name and can append automatically incremented index upon request.
  Using recording the following should be considered:
  • After recording both the raw date and the average impedance for the whole recording will be saved in two separate files (with .inp and .d12 extensions) and the impedance data will be automatically added to the clipboard content.
  • The optional automatically appended index contains three digits and starts from 001.
  • If the recording process is stopped before its end, the available data will be saved into the file.
  • After recording the next excitation signal will be automatically used for subsequent measurements. The last excitation will be followed by the first one in a cyclic manner.
  • If the user specifies a new file name, the automatically incremented file index is reset to 001.
• Stop: stops the sampling or recording process, can be activated by pressing ESC also.
• Options: displays a dialog box to enter measurement options
  • Sample rate: can have the value of 256,512,1024 and 2048. The recommended value is 512. Choosing higher values may slow down processing and will produce larger output files.
  • Recording time: can be set between 1 and 120 seconds and is used to specify the duration of recording.
  • Scale excitation: the excitation signal amplitude can be forced to have a given value regardless of the excitation definition data. For asymmetric signals the maximum amplitude will be used.
  • Data format: choosing 12 bits provides output files compatible with the old analysis software, however amplitude resolution is significantly degraded and noise is increased in this case.
  • Measured channels: the user can select the channels to be measured. The first two channels are used to calculate the impedance.
  • Signal names: the user can name the signals and these names will be used to label the correspondig axis on the plots.
  • Selecting X and Y data: the user can select two signals to be displayed on the XY plot. Only measured signals can be selected.
  • All settings are remembered upon exiting from the dialog box by pressing the OK button.

Using excitations

The application can use up to 16 different excitation signals.The user can select the required signal manually using the Excitations menu or just can let the software to manage the use of the different signals. If the user starts recording, the actual signal will be used and its parameters will be displayed in the status bar. After saving the measured data, the next signal will be used automatically. The last excitation will be followed by the first one in a cyclic manner.

A sample excitation definition file can be seen here.

The period of the excitation signals is restricted, it must not be longer than 1 second and must have duration of 1 second divided by an integer between 1 and 20. The highest frequency component can't exceed 100Hz.

The Excitations menu has the following items:

• Import excitation: loads excitation definition data from a text file. The folder will be set as the default folder for loading excitation files.
• Select next excitation: selects the next excitation signal (not available during measurement)
• Select previous excitation: selects the next excitation signal (not available during measurement)

Calibration

Proper impedance calculation requires calibration. The calibration files can be imported and then will be used automatically. Upon exiting the application calibration data are saved and will be loaded at the next application starting process.

A sample calibration file can be seen here.

Note that the last used file's folder will be set as the default folder for loading calibration files.

Impedance display

The calculated impedance is diplayed at the right-bottom of the application window. The impedance plot can be turned on or off. A right-click ativated pop-up menu allows setting the plotting and processing properties.

During sampling the average impedance calculated for the last few (adjustable between 1 and 5) seconds can be displayed. Besides displaying the average, the instantaneous impedance data taken about ten times per second can also be displayed using faded colors.

When sampling is stopped, the average impedance for the displayed signal segment is calculated. Therefore scaling the signal can be used to tune the averaging interval.

The following features are available (can be accessed via mouse and keybord operations):

• Scaling: vertical and horizontal shifting and compressing and stretching of the plotted is possible.
• Default scaling: sets factory default scaling
• Automatic scaling: the data will fit into the plot in any case
• Optimal scaling: left-cliking over the bottom-left corner icon finds the optimum scaling of the actually displayed data, but will not switch automatic scaling on.
• Copy: copies impedance data onto the clipboard. You can paste the data into a spreadsheet application (like Excel) or just put into a text file.

XY plot

Two channels can be selected in the measurement options dialog box for the XY plot located in the right-top corner if enabled.

During measurement the last few signal periods (selectable from 1 to 5) are used to plot the data. If the measurement is stopped, the interval of the displayed signal segment is used.

Right-click activated pop-up menu allows to set scaling and options.

Signal display

The signal display plots raw data in real time. The plots can be individually scaled and copied onto the clipboard.

The following features are available (can be accessed via mouse and keyboard operations):

• Scaling: vertical and horizontal shifting and scaling of the signal is possible. Horizontal shifting is not available during sampling or recording.
• Numerical integration: can be toggled using the pop-up menu activated by right-clicking over the plot
• Default scaling: sets factory default scaling
• Automatic scaling: the data will fit into the plot in any case
• Optimal scaling: left-cliking over the bottom-left corner icon finds the optimum scaling of the actually displayed data, but will not switch automatic scaling on.
• Sliding or normal display mode: can be toggled
• Copy: copies data displayed on a plot onto the clipboard. You can paste the data into a spreadsheet application (like Excel) or just put into a text file.

Saving setups

The File menu is used to save measurement and display options rather than data. Most measurement and display options, excitation and calibration data are included in the saved database.

This allows easy and safe usage of stored measurement protocols and also supports sharing of protocols, excitations, calibrations.

The recently used setup files are added to the File menu.

Note that the last setup is always saved into the Windows registry upon exit and will be loaded during application starting.

Mouse operation and shortcut keys

Mouse and some keys can be used to control the measurement, manipulate data and set display options:

• Left click
  • Over the title of the axis shifts or - if CTRL is pressed - compresses or stetches the signal display. The direction can be choosen be clicking towards larger or smaller axis values from the middle of the title.
  • Over the bottom-left corner icon finds the optimum scaling of the actually displayed data
  • If SHIFT is pressed at clicking, then the default scaling is restored for the plot under the cursor.
• Right click displays a plot-specific pop-up menu to set display options.
• Double click Zooms out to the entire measurement time.
• Scrolling over the title of an axis shifts or - if CTRL is pressed - scales the signal
• Space:
  • starts sampling
  • if sampling has been started, starts recording
  • if recording has been started, restarts recording
• left and right arrow keys: horizontally shift or - if CTRL is pressed - compress or stetch the signal display.
• Tabulator: finds the optimum scaling for each plot without switching automatic scaling on.
• a: toggles autoscaling for all plots.
• z: toggles between displaying impedance spectrum and trend
• f and SHIFT+f: changes the selected frequency for impedance tracking

NDAQ24 24-bit multichannel data acquisition system software