Pilz safety controller

The Pilz PSS 4000 platform gathers a cell's safety inputs, E-stop buttons, guard-door switches, light curtains, and a SICK safety scanner, then drives rated stop commands to the robot and cell equipment over a safe fieldbus. Because the safe protocol carries the signal end to end, the achieved rating holds across the whole chain instead of degrading between devices.

How high the safety function has to reach is settled before any wiring. The cell's risk assessment sets a required performance level under ISO 13849-1 or a safety integrity level under IEC 62061, and the PSS 4000 is chosen and configured to meet it. Those PL and SIL targets live in the standards and the assessment rather than on a datasheet line, so the controller executes the safety function that the analysis already defined. The same analysis fixes the stop category and response time for each hazard, which is what the logic on the controller actually implements.

Two architectures are common in the field. In one, the PSS 4000 runs the cell's safety logic and its standard automation from a single project, cutting the parts count and unifying the tag names. In the other, it sits as a dedicated safety layer beside a general-purpose PLC or a broader safety PLC integration, keeping safety and process code with separate teams. Choose the combined build when the cell is small to medium and one controls team owns it end to end. Choose the separate layer when plant standards or team boundaries require isolated safety code. Both patterns satisfy the standards when they're engineered and validated correctly.