Trust Nothing in the Middle: IEC 61784-3 Functional Safety Fieldbuses and the Black Channel

Deep End Era. Engineering with Sankalp · Oct 28, 2026 · 1h 3m

At the Al Sahil Gas Complex, a new compressor's emergency shutdown signals are to travel over PROFIsafe instead of copper. Mariam Al Hosani, the operator's functional safety lead, is not convinced; Diego Ferrer, the EPC's lead instrument and control engineer, has to convince her. Between them, over an argument that lasts most of a project, they explain the black channel, the eight ways a message can go wrong, the arithmetic that turns CRC lengths into SIL claims, and the plant-floor details, from addresses to watchdogs, that decide whether the arithmetic holds.

Chapters

00:00:00 Copper versus…