Two different jobs that get confused. Safety protects people from the machine — CODESYS Safety is a separate, certified runtime for SIL 3 logic. Security protects the controller from attackers — encryption, user management, signed apps. You need both, and they're not the same thing.
On the left, CODESYS Safety runs on its own certified runtime, isolated from your standard application — so a bug in normal logic can never compromise the safe function. On the right, work the security checklist to harden the controller against attackers; watch the score climb.
The safety side keeps people safe regardless of what the standard app does — the same "separate protected world" idea as Siemens F-CPU and Rockwell GuardLogix.
Why keep them separate? Safety is about random & systematic failures (certified, validated, signed). Security is about deliberate attacks (defence in depth). A controller can be perfectly safe and still wide open to the network — or locked down tight but with no safety function. Modern machines need both, designed in from the start.
An auditor asks why the E-stop logic runs on a separate CODESYS Safety runtime instead of in your main application.