Technical Documentation
Core concepts
Technical documentation includes drawings, circuit diagrams, parts lists, operating instructions, maintenance manuals, test reports and change records. Candidates must understand standardized drawing symbols, reference designations, revision control and document versioning. Know the structure of operating instructions: intended use, safety information, technical data, commissioning, operation, maintenance and disposal. Understand traceability: every change must be recorded with date, author and reason.
Traps in questions
- Confusing a circuit diagram with a wiring diagram or layout diagram.
- Ignoring revision status; working from an outdated drawing is a classic error.
- Writing instructions without safety warnings or intended-use statements.
- Omitting units, tolerances or reference designations.
- Failing to update documentation after a modification.
Worked example
A modification changes a sensor from 24 V PNP to 24 V NPN. Correct documentation practice: update the circuit diagram, change the parts list entry, revise the operating instructions if behaviour changes, increment the revision index, record the change in the change log, and inform maintenance. Rule of thumb: if it is not documented, it did not happen; if it is not versioned, it cannot be trusted.
Practical competence
Be able to read and produce simple circuit and layout diagrams, write a clear maintenance instruction, and maintain a change log. Understand that documentation is part of the product's legal conformity, especially for machinery safety.