Feedback Connections User Guide

Version: 3.9.1

1 Nomenclature

Term	Definition
MADE	Maintenance Aware Design Ecosystem
FMEA	Failure Mode and Effects Analysis

2 Introduction

Feedback connections are represented using broken lines with an (F+) or (F-) label that represents indirect impacts between two different components. These are automatically defined in MADE (with broken lines) when you connect an outgoing flow to an input flow that already has an existing connection.

Feedback lines are used to provide impacts (such as resistance or inertia) that do not have a direct flow path. Negative feedback (F-) is particularly useful for providing a feedback flow from one component to the preceding component to simulate the back effect of power transmission (e.g. the impact of a reduction in torque of a shaft on the component connected before it).

Figure 1 ("Simple feedback representing inertia of a shaft item") shows: IN(1) → Torque → Gearbox → Angular velocity → Shaft → Torque → OUT(1), with a dashed feedback line labeled "F -" running from the Shaft's Torque output backward to the Gearbox input, and another "F -" label at the Shaft's own output — illustrating the negative feedback path used to model the back-effect of the Shaft's inertia/resistance on the upstream Gearbox.

A feedback line does not propagate a flow quite the same as normal flows in MADE. While feedback lines do impact the response value at the target, they are not counted as unique paths for FMEA analysis (MADE does not consider feedback lines as separate failure paths).

Since Feedback lines are automatically created when a component already has an input flow, these may be accidentally added to the model. To fix this, new input sources can be added to accommodate the additional inputs without turning them into Feedback.

Figure 2 ("Two indirect flows (Left) vs Two direct flows (Right)") contrasts two modeling configurations:

• "Instead of this configuration" (left): Component 1 → Component 4 (direct flow), with Component 2 and Component 3 both feeding into Component 4 via dashed F- feedback lines (labeled "F-F-" and "F-"), because Component 4's input was already occupied by Component 1's connection — an unintended/accidental feedback configuration.
• "Try this configuration" (right): Component 1, Component 2, and Component 3 all connect to Component 4 via separate direct (solid) input flows/ports, avoiding the accidental feedback lines entirely.

This is the guide's core practical guidance: when multiple components need to feed the same downstream component, add distinct input ports/sources on the target rather than reusing a single input (which MADE will silently convert into an (F+)/(F-) feedback connection, excluded from FMEA path-counting) — see Figure 2's recommended right-hand configuration.