jc_0653: Delay block layout in feedback loops

Guideline Publication

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

Sub ID Recommendations

  • NA-MAAB — a

  • JMAAB — a

MATLAB Versions

All

Rule

Sub ID a

Delay block in feedback loops across subsystems shall reside in the hierarchy that describes the feedback loop.

Custom Parameter

Not Applicable

Example — Correct

Delay block resides in the hierarchy that describes the feedback loop.

Example — Incorrect

Delay block resides in a subsystem that is nested within the hierarchy which describes the feedback loop.

Rationale

Sub ID a:

  • Prevents double placement of the Delay block.

  • Clarifying the extent of diversion improves reusability.

  • Improves testability; it is difficult to test a subsystem that contains a Delay block on its own because past values cannot be entered directly.

Verification

Model Advisor check: Check for avoiding algebraic loops between subsystems (Simulink Check)

Last Changed

R2020a

Version History

Introduced in R2020a