sgrid

Scilab Function
Last update : Jun 1997

sgrid - s-plane grid lines.

### Calling Sequence

  `sgrid()`
  `sgrid('new')`
  `sgrid(zeta,wn [,color])`

### Description

Used in conjonction with evans, plots lines of constant damping ratio (`zeta`) and natural frequency (`wn`).

  sgrid(): add a grid over an existing continuous s-plane root with default values for `zeta` and `wn`.
  sgrid('new'): clears the graphic screen and then plots a default s-plane grid
  sgrid(zeta,wn [,color]): same as `sgrid()` but uses the provided damping ratio and natural frequency.

### Examples

    H=syslin('c',352*poly(-5,'s')/poly([0,0,2000,200,25,1],'s','c'));
    evans(H,100)
    sgrid()
    sgrid(0.6,2,7)

### See Also

`evans`,