Session 4: vector input outputs

We have already seen that blocks can have more than one input. They can also have more than one output and, moreover, each input and output can be vectorized. Thus to each port, it is associated a size. When connecting an output port to an input port, port sizes must be equal.

Construct the following diagram by copying blocks from the palettes

Scicos diagram with multiplexer
The Mux (multiplexer) is in the Branching palette. This block can have any number of inputs (each can be vectorized); the output is a vector obtained as concatenation of the inputs. The only parameter of this block is the number of inputs; there is no need to specify the size of each input. Scicos figures the size by examining the blocks to which each input port is connected. In the above example, the inputs are of size one and consequently the output is a vector of size 2. Similarly for the  Scope (here is no need to specify the size of the input vector, it is adjusted automatically. 

Simulate
      The simulation result is given below. 

The Scope display

Note that the Scope, when it receives a vector input, superimposes the corresponding signals.

Modify the diagram as follows
      The Demux block does exactly the opposite of Mux, i.e., it cuts the input vector into smaller size vectors.

Demux block undo what Mux has done
To avoid that the outputs of Scope and MScope be displayed on the graphics, make sure to set MScope parameters such that it uses a different graphics window.
Modify the diagram as follows
      The new block realizes the linear dynamical system:
 
dx/dt = Ax + Bu                       u is the input vector, x the internal state
    y  = Cx + Du                        y is the output

The new block is a linear dynamical system
Modify block parameters of the new block as follows
      Note that the block parameters are: A, B, C and D matrices.  They define the sizes of input and output vectors.

Parameters can be defined using Scilab syntax
Complete the diagram as follows

The dimensions of input output vectors are compatible
Ready to go on?
 Yes, I am ready for Session 5
 No, I want to go back
For more information about Scicos, send an e-mail to Doctor Scilab: Scilab@inria.fr

 

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