From the Archives

Since I have been completely swamped with work and haven’t really had time to do any more PHP learning, I decided to write about a program I wrote ages ago in 2ooo. I was looking through my old files and came across the manual that I wrote, plus all the source code which I somehow still have :-).

The program was written for a solar energy project that I was involved in. For my Masters research project I built and monitored the performance of a Compound Parabolic Concentrator for solar panels in equatorial latitudes. I will be posting more about that on my physics page and will add a link here. The purpose of the concentrator was to increase the illumination levels on a solar panel, subsequently increasing its efficiency. For the duration of my project, I collected all the data manually, which sometimes involved sitting out in the sun for hours!! There was also an element of error introduced by this method because I had to read five different meters each time (in 15 minute intervals). I then applied calculations to this data, did my analysis, etc.

After my thesis was done and I passed (of course :-)), my supervisor and I decided to try to automate the data collection process for future projects. We bought and installed a Computer Boards I/O card and wired various components to make the system work. (Computer Boards was renamed Measurement Computing). I programmed the system and tested it, and afterwards wrote a complete User and Technical Manual for it. The system was programmed in Visual Basic 3.0 on a PC running Windows 95, which I still believe to be one of the most stable OS’s MS has produced.

Quoting from the User Manual:

The PVPM system comprises three main components; the CPC/PV system, the interfacing component and the software component. The CPC/PV system comprises a PV panel equipped with low-concentration parabolic reflectors. The interfacing component includes a constant voltage electronic bridge, an IO card and a PC. The software component is a program that collects and interprets data from the CPC/PV system via the interface.
The bridge for which this program was designed is a constant voltage bridge. This means that it keeps the voltage reading across the panel at a constant value so that only the current varies. Moreover, the bridge converts the current reading into a voltage reading and steps down the voltages so that they can be fed into the computer. Conversion factors are provided with the bridge to enable the user to convert the readings back to the actual voltage and current values. These conversion values are:

Current: Multiply by 14.8
Voltage: Multiply by 8.5

The IO card for this program is a Computer Boards card. The details concerning this card are comprehensively covered in the technical manuals supplied with the card.
The output from the card is in counts, which the PVPM program then converts to voltages before the bridge conversion factors are applied.
The card comes with its own installation software, which is used for configuration purposes. Libraries for different programming languages are also provided in the Universal Library diskette. For this case, the software for the data access has been written in Visual Basic 3.0. The program has been left in its raw form (not compiled as stand alone) so as to enable future modifications when necessary. The setback with this, however, is that the program can only be run in a PC that has the Visual Basic 3.0 program installed and all the necessary files must be manually loaded. Details of this are given in the Technical manual that accompanies this user manual.

The user manual gives a screen-by-screen description of how to use the PVPM software while the technical manual gives the source code for the software.

The manual was written in MS Word, and I created all the images and icons using MS Paint.

Here are some screen shots of the program interface:
Single Channel Mode
Multi Channel Mode
Loading Image
This last image is what loaded first when the program ran, much as a flash image would load now.

The plan was to transition from VB3.0 and recode the system using LabView, and we bought and installed the software, but I left the institution before that part of the project begun. I lost contact with the research group after some time and I’m not even sure if they recoded the system and if the project is still running.

User and Technical Manual for the PVPM System

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