10 current meters. The specific GEDAP programs used in each of these batch
files will be discussed in the next two chapters.
The GEDAP software system runs in a standard Windows NT Command
Prompt window. By typing "GHELP" at the command prompt, the user will
obtain the main menu of the on-line documentation, as shown in Figure 37. This
initial GHELP browser screen is split into three sections. The upper section
includes two hyperlinks, one gives a general description of GEDAP and the other
provides a complete list and description of all GPLOT commands. The middle
section of this figure includes hyperlinks to the eight GEDAP program
categories, which were represented earlier as the eight blocks at the bottom of
Figure 36. The lower section includes hyperlinks that provide access to all of the
subroutine libraries. The user can click on the highlighted hyperlinks to view lists
of all of the available programs and subroutines. Similarly, the user can click on
any highlighted program name to obtain a complete description of the particular
program or subroutine.
Additional information about GEDAP may be obtained from the GEDAP
Users Guide for Windows NT, Miles (1997). Additional information regarding
the GPLOT graphics package can be found in the GPLOT User's Guide
(Dominis Engineering Ltd. 1992).
Display System for ADV Digital Data
A problem encountered while procuring the ADV's for the LSTF was that
the simultaneous digital output signals transmitted from the 10 ADVs exceeded
the capacity of the PC-based serial communication port. Therefore, each ADV
was upgraded with additional hardware to generate analog output voltage signals,
as an alternative means of collecting ADV data. The analog output voltages are
transmitted through ten 130-m-long cables, to the MTS data acquisition and
control system. However, the analog output signals only include the output
voltage from each velocity component and one additional output signal, which is
proportional to the mean signal amplitude. The analog output signals do not
include all of the information that can be obtained using RS485 serial
communication (digital data), such as the SNR for each velocity component, as
well as other diagnostic information.
To solve this problem, a second computer is used in the LSTF control room
for real-time display of the digital data obtained using RS485 serial
communication. However, digital data can be displayed from only one ADV at a
time, because of the data transfer rate limitations through the serial
communications port. Therefore, the user must toggle from one ADV to the next
to inspect the operation of each ADV, while conducting an experiment. The real-
time display screen is shown in Figure 38. The upper section of the real-time
display screen shows the numerical values of velocity and other diagnostic data,
such as SNR, correlation, and the standard deviation for each component of
velocity. The middle section of the screen shows real-time plots of SNR,
correlation, and velocity data. The lower section of the screen lists all of the
command options, such as a toggle switch, which allows the user to display the
output from a different ADV.
59
Chapter 6
Experiment Control, Data Acquisition, and Analysis Packages
Previous Page
