Safety PLC Architecture in Robot Cells
Design principles
| Principle | Practice |
|---|---|
| Separation | Safety functions independent of standard control logic |
| Determinism | Fixed scan, no cloud or non-deterministic links |
| Diagnostics | Detect sensor faults, not just triggered states |
| Documentation | Every function mapped to a hazard |
| Testing | Periodic proof tests with recorded results |
Common mistakes
- Routing safety signals through ordinary PLC logic to save wiring.
- Leaving safety parameters editable without access control.
- Adding a function and not updating the risk assessment.
Required performance levels follow from the risk assessment. Confirm with a competent specialist.