Blocks can inherit data types from a variety of sources, including signals to which they are connected and particular block parameters. The following table lists the types of inheritance rules that a block might specify.
Simulink automatically determines the output data type of the block during data type propagation. In this case, the block uses the data type of a downstream block or signal object.
The block uses the data type of its sole input signal for its output signal.
The block uses the data type of its first input signal for its output signal.
The block uses the data type of its second input signal for its output signal.
The block uses an internal rule to determine its output data type. The internal rule chooses a data type that optimizes numerical accuracy, performance, and generated code size, while taking into account the properties of the embedded target hardware. It is not always possible for the software to optimize efficiency and numerical accuracy at the same time.
To enable proposals for results that specify an inherited output data type, in the
Fixed-Point Tool, in the Convert Data Types section of the toolstrip,
under Settings, set the Convert inherited types
For objects that specify an inherited output data type, the Fixed-Point Tool proposes a new data type based on collected ranges and the specified proposal settings.
The Fixed-Point Tool proposes data types only for the Output data type parameter of a block or model object. It will not propose for other block data types, such as the Accumulator data type of a Sum block, or the Gain parameter in a Gain block.
The Fixed-Point Tool will also not propose for the following model objects if they use an inherited output data type.