A Software Tool was designed to allow the optimal use of the probe and to show the results of the measurements. The following main steps have been followed:
1) The general user and specific interface requirements for the probe and the pressure compensation system were determined;
2) An interface design which meets all the requirements previously determined was created and implemented;
3) The software tool was evaluated by a group of representative users and through a series of tests.
The design effort resulted in a general purpose Software Tool that is highly adaptable and expandable. Figure 3 shows the Configuration Mask of the application, devoted to the initial set of parameters related to all instrument features. The mask allows the user to configure different kinds of current measurements, saving and displaying data in graphic or text formats and generating a report. A vocal synthesis system also provides an audio output of the results. In detail it is possible to configure:
• The conditions for the acceptance of the measurements. The tool calculates the standard deviation of the data in a given number of samples that can be set. When the standard deviation is lower than a pre-setable threshold, the current measure is accepted and
• The pressure compensation parameters. The user can modify the pressure compensation system parameters and check the status of the probe and of the pressure sensor. A patented algorithm was developed to set the minimum and maximum pressure level range and the absolute maximum upper and lower pressure limits for optimal compensation. If the maximum limits are exceeded, the measurement is aborted.
• The voice synthesizer parameters. Speech synthesis was implemented to improve the information capacity of the user. Many different
types of information are provided to the user like suggesting where to place the probe, the name of the selected point and so on. All of this information can be very useful during operator training.
• The on-line help. The interactive help provides both text and speech answers. The operator can set the level of interaction required.
Figure 3: The Configuration Mask of the Software Tool.
The software package manages different kinds of current measurements, in a range of 30 to 3,000 nA, saving and displaying data in graphic or text formats (see Figure 4). All data either in text or in graphics form are stored in a data base together with all the information related to the test session. The measured current and the pressure exerted on the probe during the measurement can be displayed as a function of the time in a specific pattern (Figure 5). In order to minimize the measurement error, the developed algorithm is able to automatically
compensate the measure as a function of the pressure exerted on the probe. As can be seen in Figure 5, thanks to the action of the compensation algorithm, the current (red line) remains unaffected by the large variations in the pressure exerted on the probe (blue line).
Figure 4: Displaying data in graphical and text formats.
Figure 5: Displaying of the measured current and of the pressure exerted on the probe during the measurement.