Source Selector

Block-library: DUBSI

The Source Selector block provides a convenient method to choose between all possible Source signals from Simulink and DUBSI by allowing the user to select the required source signal from a list.

The block has been implemented by means of a Configurable Subsystem block from the Signals & Systems library of Simulink, which has been linked to the special blocklibrary sources_collection. All blocks in sources_collection have two things in common: they do not require any input signals, and they only generate one continuous output signal.

The figure below shows the default contents of this blocklibrary:

A user who applies the Source Selector block in his or her own systems first needs to select the required source signal from the 'Block choice' list, and subsequently needs to specify the parameters for the selected source block. In the figure below, this has been illustrated for the Sine Wave source block:

It is possible to add new source blocks to the sources_collection library, as long as they too do not require any input signals and generate only one continuous output signal. However, this is quite cumbersome due to the less-than-perfect implementation of the Configurable Subsystem block in Simulink 3.0. The suggested procedure to enhance the list of options is as follows:

1. first, create a backup of the DUBSI library,
2. unlock this library,
3. click on the block Source Selector, open the Mask dialog, and copy the line from the 'Block Help' area,
4. close the Mask dialog and delete the block Source Selector,
5. copy a Configurable Subsystem block into the DUBSI blocklibrary,
6. double-click this block, and enter sources_collection (in lower case) as library name,
7. rename the block to Source Selector (don't use any other name; you may end up breaking library links without knowing it),
8. open the Mask dialog and paste the copied line to the 'Block Help' area,
9. close the Mask dialog and save the blocklibrary.

Due to the same less-than-perfect implementation of the Configurable Subsystem block, the contents of the Source Selector are not always updated correctly immediately after opening a system in which this block is applied. If that happens, it is necessary to update the system once more, using Ctrl+D or the 'Update Diagram' option in the pull-down menu.