modelRealNinOperation

Real comparison interface

Information

Description

Real math operations.

Fixed Point numbers

When using fixed point real numbers, Nbit is the number of bits that can be represented. The range is

  Xfp in [-2^{Nbit - 1} + 1  ,...,  2^{Nbit - 1}]

Then it is possible to define a scaleFactor

  X = Xfp/scaleFactor

When the Fixed Point representation is selected (through the selection of the boolean flag FixedPoint), each input number u[:] is converted into an integer Ufp[:]

  Ufp[:] = u[:]*scaleFactor

then the result of the math operation Yfp is computed and converted into the output value y. The output conversion depends on the math operation performed.

Saturation

To note that the Fixed Point numbers have a maximum and minimum value. In order to avoid saturation when performing the computations, the number of bit as well the scale factor have to be choosen carefully.

Parameters

Type	Name	Default	Description
Modelica.Units.SI.Time	Ts	0.1	sampling time
Integer	nInput	1	number of inputs
Boolean	useInputs	true	=true, if inputs are enabled
Fixed Point
Boolean	FixedPoint	false	Use fixed point real numbers
Integer	Nbit	16	Number of bits for representing the real numbers
Real	scaleFactor	1	Scale factor for Fixed Point numbers
Integer	MAX	integer(2^(Nbit - 1))	maximum number that can be represented with Fixed Point notation
Integer	MIN	-integer(2^(Nbit - 1)) + 1	minimum number that can be represented with Fixed Point notation

Connectors

Type	Name	Default	Description
Modelica.Blocks.Interfaces.RealInput[nInput]	u		input vector
Modelica.Blocks.Interfaces.RealOutput	y		output

Components

Type	Name	Default	Description
Integer[nInput]	Ufp		floating point converted input
Integer	Yfp		floating point converted output

Revisions

Industrial Control Systems (v 1.0.0) : April-May 2012