Main Content

jc_0171: Clarification of connections between structural subsystems

Since R2020a

Guideline Publication

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

Sub ID Recommendations

  • NA-MAAB — No recommendations

  • JMAAB — a, b

MATLAB Versions



Sub ID a

A minimum of one signal line shall connect two structural subsystems.

When a two-way signal connection exists between two structural subsystems (A and B), each direction shall be connected to at least one signal line.


Using Goto and From blocks to create buses or connect signals to a Merge block.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID b

Signals that are not used within a structural subsystem shall be input to a structural subsystem. These signals shall not be output to other structural subsystems or basic blocks.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Signals that are not used in the subsystem are connected to avoid crossing of signal lines.


Sub ID a:

  • Clarifies structural subsystem connections and execution order.

Sub ID b:

  • Eliminating unnecessary connections clarifies the relationship between connections.

  • Deviation from the rule can cause to confusion due to unused input/output signals.


Model Advisor check: Check connections between structural subsystems (Simulink Check)

Last Changed


Version History

Introduced in R2020a