<< PLAGE_LINEAIRE_INT CPGE - Xcos toolbox REP_TEMP >>

CPGE - Xcos toolbox >> CPGE - Xcos toolbox > REP_FREQ

REP_FREQ

Frequency plot

Block screenshot

Contents

Palette

Description

This block allows to plot frequency diagrams in Bode, Black or Nyquist plans, in open or closed loop, for any linear function.

The selected transfer function is the one located between the two blocks GRANDEUR_PHYSIQUE which are specified as input and output points.

A frequency diagram is associated to each block. It is possible to plot many blocks REP_FREQ in a single diagram in ordre to obtain multiple frequency plots (typically those in open and closed loops).

In the example, it is possible to plot the Bode diagram in open loop (betwen EBO and SBO: 5/(s (1+s)), and also the Bode diagram in closed loop (between EBF and SBF).

It is also possible to obtain the plot of the gain and phase margins, when it is relevant

Nota: the temporal entry can be of any type because no temporal entry or scope is necessary for frequential plot.

Dialog box

The setting of the block is done by 4 dialog boxes.

The first dialog box allows to select the type of plot, associated to a number: Bode (1), Black / Nichols (2) or Nyquist (3).

The second dialog box allows to specify the input and output points of the transfer function.

The third box allows to precise the range of pulsations to plot, with the number of calculated points for the plot of the diagram.

The fourth box allows to ask (or not) the plot of the gain and phase margins. Indicate 0 or 1.

Case of a delay block in the diagram

The REP_FREQ block is compatible with any linear block diagram, and partially compatible with the presence of pure delays (TIME_DELAY block).

In the case of the delay block in factor of the transfer function, which means before or after or any equivalent situation, the delay is considered in an exact way with the toolbox IODELAY.

In the case of the delay blockinside of a loop, it is not possible to consider the delay in an exact way. The delay block is then approximated by a transfer function (Padé approximant) with order chosen by the user. An order of 10 is recommanded. In function of the delay and of the Padé approximant, a maximal frequency is calculated indicating that, beyond this frequency, the approximation becomes incorrect.

Default properties

Example 1

This diagram shows the use of the REP_FREQ block to plot the Bode diagram of a second order function.

Open the example in Xcos !

Example 2

This diagram shows the use of two REP_FREQ blocks to plot the Bode and Black diagrams, in open and closed loops. Below, the Black diagram of the open loop.

Open the example in Xcos!

Interfacing function

Computational function

See also


Report an issue
<< PLAGE_LINEAIRE_INT CPGE - Xcos toolbox REP_TEMP >>