Chapter 3 Building System Connections
Xmath Control Design Module 3-8 ni.com
append( ) performs a check to make sure both Sys
1
and Sys
2
have the
same sample rate, and adopts this rate for the appended system. Any initial
conditions on the states are also appended columnwise.
connect( )
Sys = connect(Sys1,{K,M,N})
The connect( ) function performs a general interconnection around a
system. This provides two basic capabilities:
• constant gain feedback
• general input–output interconnection
In its simplest form,
connect( ) can be used to wrap constant gain
feedback around a system. The keyword
K, used to specify feedback gain,
also can be used to specify which outputs are fed back to the input of the
system. By specifying the optional keywords
M and N, you also can specify
input and output gains.
General input–output interconnection is applicable to the block form
system provided by
append( ), as described in the append( ) section.
Parameters used in the
connect command are illustrated in Figure 3-3.
Notice that feedback is defined with a positive sign.
Figure 3-3. Parameters Used with the connect Command
A
A
1
0
0 A
2
= B
B
1
0
0 B
2
=
C
C
1
0
0 C
2
= D
D
1
0
0 D
2
=
u
1
u
k
uyy
1
Sys
1
N
Sys
M
+
+
K
