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How the Software Determines Properties of Connected Models

When you interconnect models, the operation and the properties of the models you are connecting determine the resulting model's properties. The following table summarizes some general rules governing how resulting model property values are determined.

PropertyExpected Behavior

When connecting discrete-time models, all models must have identical or unspecified (sys.Ts = -1) sample time. The resulting model inherits the sample time from the connected models.


In general, the resulting model inherits I/O names and I/O groups from connected models. However, conflicting I/O names or I/O groups are not inherited. For example, the InputName property for sys1 + sys2 is left unspecified if sys1 and sys2 have different InputName property values.


All connected models must have identical TimeUnit properties. The resulting model inherits its TimeUnit from the connected models.


A model resulting from operations on tf or zpk models inherits its Variable property value from the operands. Conflicts are resolved according the following rules:

  • For continuous-time models, 'p' has precedence over 's'.

  • For discrete-time models, 'q^-1' and 'z^-1' have precedence over 'q' and 'z', while 'q' has precedence over 'z'.


Most operations ignore the Notes and UserData properties. These properties of the resulting model are empty.

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