Main Content

db_0143: Usable block types in model hierarchy

Since R2020a

Guideline Publication

Control Algorithm Modeling Guidelines - Using MATLAB®, Simulink®, and Stateflow®

Sub ID Recommendations

  • NA-MAAB — a

  • JMAAB — a

MATLAB Versions



Sub ID a

Model levels shall use only the block types that are defined for the layer type. Clearly defined layer types restrict the number of blocks that can be used.

Block restrictions:

  • (R2011a and earlier) Enable block cannot be used at the root level of the model.

  • Action ports are not permitted at the root level of a model.

Layer restrictions:

  • Data flow layers that are used for basic blocks only.

  • Other than data flow layers, layers can include blocks that are used for structural subsystems and all other layers.

Blocks that can be used for all layers include:

Custom Parameter

Layer type

Block type


Sub ID a:

  • Readability is impaired when subsystems and basic blocks are used in the same layer.


Model Advisor check: Check for mixing basic blocks and subsystems (Simulink Check)

Last Changed


Version History

Introduced in R2020a