Hidden in a footnote, it stated: “PPC-R22.1 requires a dedicated Sercos phase-up sequence. If any slave device on the ring replies before the master is ready, the cycle timeout occurs.” Marina realized a new proximity sensor (installed last month) was booting up 200ms faster than the old one, confusing the controller.

"Empty!" his apprentice, Leo, yelled back. "Just some old fuses and a 2015 calendar."