Technical Support

Useful hints on the use of the Virtual Physical Laboratory.

This page addresses some of the most frequent questions arising out of the use of the Virtual Physical Laboratory in schools and colleges. It is not a comprehensive list.

1 – Programs will not run: “Unable to locate the LabVIEW Run-Time Engine.”

This happens whenever a simulation tries to run on a computer where the software has not been properly installed. It can be resolved in the following way:
Copy ‘lvrt.dll’ (normally located in c:\program files\virtual physical laboratory) and ‘lvsound.dll’ (normally located in c:\program files\virtual physical laboratory\sound\data) into the folder containing the simulation that will not run. Note they they should be copied (not cut & pasted or dragged). 

2 – Colours of graphs.

The colour red does not project very well, especially narrow red lines on a black background. The solution offered here will work in most cases (but not all).

To change the colour of a line on a graph, right click somewhere inside the graph and select ‘show’ and then ‘legend’ (some graphs already have the legend showing). A box near the top right hand corner of the graph will appear. Right click inside it, and you will be able to select ‘colour’. A colour palette will appear. Select your preferred colour and it will change the plot accordingly. You can then hide the legend box again by right clicking somewhere inside the graph and selecting ‘show’ and selecting ‘legend’ again. Your change will be a temporary one; it will be lost as soon as you quit the simulation.

Changes of colour may also be advisable in some simulations in order to make things easier for colour blind pupils.

Notice also that right clicking on the legend also offers the possibility of changing the ‘linewidth’. This may be a useful change to visually impaired students or where the projection is particularly poor.

3 - Re-scaling graphs, gauges, dials, knobs and sliders.

If a graph, gauge, dial, knob or slider goes out of range, or if you want to change the range in order to improve resolution, left-click and drag over the number at the top (or bottom) of the scale and type the new value you would like to have. The scale should automatically adjust to the new value. Your change will be a temporary one, it will be lost as soon as you quit the simulation.

If you want a graph to automatically re-scale, right click somewhere inside the graph and select ‘AutoScale X’ or ‘AutoScale Y’

4 – Using just one or two simulations without installing the whole package. Simulations can be run independently without recourse to the top level library.

All the files which make up the Virtual Physical Laboratory are contained in a folder on the hard drive (normally in c:\program files\virtual physical laboratory). They are grouped by the same chapter divisions as shown in the tope level program of VPLab.

Create a new directory with a name of your choice using windows explorer. It can be created anywhere on your computer, including on a USB memory stick, or a shared folder on a network.

Two dynamic link libraries are needed for this to work. ‘lvrt.dll’ (normally located in c:\program files\virtual physical laboratory) and ‘lvsound.dll’ (normally located in c:\program files\virtual physical laboratory\sound\data) will need to be copied (not cut & pasted or dragged) into your new directory. Now copy (not cut & paste, and not drag) any of the simulations you want into your new folder.

These simulations will now run on any machine supporting windows 95 onwards, without needing the full installation. If using a USB memory stick, it can be transported to any other computer, and the simulations can be made to run simply by using windows explorer and double clicking on any of the ‘*.exe’ files that you have selected to copy.

5 – Printing diagrams from the VPLab simulations.

The reason the majority of the VPLab screens are black is that it is much quicker to refresh the screen, and the graphics side of the simulations can run more smoothly. If you want to print part of a screen, the semi-satisfactory way to do this is as follows:

Press “Shift-Print Screen”, and then open Microsoft Paintbrush (Normally “Start-Programs-Accessories-Paint). Now press “Ctrl V” (or right click and select ‘paste’). The entire screen should have dumped into the Paint Brush window.click on the select rectangle button of paintbrush to box the part of the image you want. While it is still boxed, click on the ‘Image’ button at the top of the Paint Brush window and select ‘invert colours’ All the black should have turned to white, and all the colours are unrecognisable! This might be good enough for your purposes, but if you want to recover the original colours carry out the next step.

Now click on the ‘fill with colour’ button on the left hand side of the Paint Brush Screen (it looks like a bucket of paint), and select the black colour at the bottom left hand side of the screen and paint all the white back to black again! Then select ‘Edit – Select all’ (or Ctrl A) and then ‘Image-invert colours’ again in order to return back to the original colours (without the black). Notice that the screen pieces contained inside hollow letters may need some special attention!

6 – Printing Text from the VPLab simulations.

Unfortunately this cannot be done satisfactorily. It was not a deliberate policy, but just the way it turned out. They can be dumped as graphics, but this is not satisfactory. Sorry!

7 – Exporting experimental data from the VPLab simulations.

Sorry, this cannot be done (except in the time honoured fashion of pencil and paper!)