Glossary · Requirements and interfaces
Interface requirement
German: Schnittstellenanforderung
In systems engineering, an interface requirement specifies what must be exchanged or matched across the boundary between two system elements or systems: signals, data, protocols, timing, physical connections, power or mechanical fit.
- Systems engineering
- Data and interfaces
In one sentence
An interface requirement specifies what must be exchanged or matched across a boundary between system elements: signals, data, timing or fit.
Example
The robot cell must send a 'cell safe' signal to the line PLC via two-channel hardwired contacts with a reaction time under 20 ms.
How it applies
- Engineering: Interface requirements are defined jointly by both sides and captured in an Interface control document (ICD) or Interface specification.
- Integration: Many integration failures come from implicit assumptions (units, ranges, byte order); explicit interface requirements make them testable.
- Documentation: For operators and integrators, interface requirements become connection diagrams, signal lists and communication settings; the documentation team should publish them from the same source.
- Verification: Interface requirements are verified in integration tests with both sides present or with simulators; record the tested versions of both sides, because a later update on one side can break the interface.
Interface requirement vs. interface specification
The interface requirement states what the interface must achieve. The interface specification describes how it is realized in detail (pins, telegrams, data types) and should trace back to the requirement.