Scilab Home page | Wiki | Bug tracker | Forge | Mailing list archives | ATOMS | File exchange
Please login or create an account
Change language to: Français - Português - 日本語 - Русский

Please note that the recommended version of Scilab is 6.1.0. This page might be outdated.
See the recommended documentation of this function

nicholschart

Nichols chart

Calling Sequence

`nicholschart([modules] [,args] [,colors])`

Arguments

modules

real vector ( modules (in dB))

args

real vector (phases (in degree))

colorss

a scalar or a vector, the color indices for isogain and iso phase curves

Description

plot the Nichols'chart: iso-module and iso-argument contours of `y/(1+y)` in `y` phase/gain plane

`nicholschart` may be used in cunjunction with black.

The default values for `modules` and `args` are respectively :

`[-12 -8 -6 -5 -4 -3 -2 -1.4 -1 -.5 0.25 0.5 0.7 1 1.4 2 2.3 3 4 5 6 8 12]`

`[-(1:10) , -(20:10:160)]`

Remark

Traditionally, the type of a calling sequence for `nicholschart` is: nicholschart(modules=gains, args=phases, colors=colors), but the following calling sequence is also allowed: nicholschart(gains, phases, colors).

Examples

```//Nichols chart
clf()
nicholschart(modules=[-6 -3 -1 1 3 6], args=[-1 -20 20 40 80 160 180]);```

```//Black diagram with Nichols chart as a grid
s=poly(0,'s');
Plant=syslin('c',16000/((s+1)*(s+10)*(s+100)));
//two degree of freedom PID
tau=0.2;xsi=1.2;
PID=syslin('c',(1/(2*xsi*tau*s))*(1+2*xsi*tau*s+tau^2*s^2));
clf();
black([Plant;Plant*PID ],0.01,100,["Plant";"Plant and PID corrector"]);
//move the caption in the lower rigth corner
ax=gca();Leg=ax.children(1);
Leg.legend_location="in_lower_right";
nicholschart(colors=color('light gray')*[1 1])```

See Also

• black — Black-Nichols diagram of a linear dynamical system
• nyquist — nyquist plot
• hallchart — Draws the Hall chart

History

 Version Description 5.5.0 Calling sequence allowed: nicholschart(gains, phases, colors).

Comments

Add a comment:
Please login to comment this page.

 Report an issue << m_circle Plot and display nyquist >>

 Scilab EnterprisesCopyright (c) 2011-2017 (Scilab Enterprises)Copyright (c) 1989-2012 (INRIA)Copyright (c) 1989-2007 (ENPC)with contributors Last updated:Fri Apr 11 14:06:51 CEST 2014