Never Wait, Always Remember: PLCs and IEC 61131

Deep End Era. Engineering with Sankalp · Oct 28, 2026 · 55m

A bottling line stops dead at ten past six on a Monday because a cleaner nudged a photo eye. Episode one hundred and thirty six opens the grey cabinet beside the line to explain the programmable logic controller: born in 1968 to replace walls of relays, still programmed in drawings electricians recognise, and running a read-think-write loop a hundred times a second that must never wait. We follow a controls engineer as she rewrites tangled ladder logic as a self-explaining state machine, then look at safety controllers, the 2025 edition of IEC 61131-3, the move to virtual PLCs in data…