notes from the
bench.
Write-ups from an automation workbench: redundant PLCs, industrial networks, HMIs, and the edge PCs that tie them together. What was built, how, and what broke along the way.
Notes
Registering a domain, hosting a static site on Cloudflare Pages straight from a private GitHub repo, and forwarding email to it, plus the handful of gotchas that turned up the second time through.
Two controllers, one address: CODESYS redundancy on WAGO PFC300s, a virtual IP that follows the active PLC, and an OPC UA struct that every HMI reads, so failover never shows up downstream.
One outbound Cloudflare Tunnel from an edge PC does two jobs: login-gated HMIs any browser can open, and private engineering access to the PLC subnet that only enrolled laptops can reach.
A set of plain-HTML reference pages for the tools an automation engineer touches every day, from Structured Text and Modbus registers to systemd and regex.