National Instruments 370753C-01

Chapter 3 Building System Connections

Dynamic systems also can be flexibly combined with scalars and

compatibly sized matrices using the operators in Table3-1. A compatibly

sized matrix is one having the same dimensions as the dynamic system’s

D matrix (row size equal to the number of outputs and column size equal

to the number of inputs).

Operations performed with a dynamic system and a matrix M as the

operands internally handle M as a pure-gain system implemented as

system([],[],[],M).

The * operator can be used with a system and a PDM to find the time

response of the system to the general input data stored in the PDM. For

a detailed description of time simulation in Xmath, refer to the General

Time-Domain Simulation section of Chapter 4, System Analysis.

Sys = adj[Sys1] If Sys1 is in state-space form and comprises the matrices

(A1,B1,C1,D1), Sys is the adjoint system and comprises

(–A1',C1',B1',D1'). If Sys1 is a transfer function, it is

converted internally to state-space form.

p1/p2 Alternate method to create a system, where p1 and p2

are the numerator and denominator polynomials,

respectively; does not allow the use of keywords.

Sys = inv(Sys1) The inverse (pseudoinverse) of a system can be found

using inv(Sys1). If Sys1 is a transfer function,

inv(Sys1) is the reciprocal of the transfer function.

If Sys1 is a state-space system (A1,B1,C1,D1), then

Sys =system(A,B,C,D) where A,B,C,D are defined

as follows:

D = pinv(D1)

A = A1-B1*D*C1

B = B1*D

C = -D*C1

Table 3-1. Summary of Interconnection Operators (Continued)

Diagram Description