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Safety

Safety PLC

A safety-rated controller executing certified safety functions, often alongside standard control tasks in machine environments.

Critical criticalityLevel 1 (safety)

What it does

Executes safety logic (e-stops, guard interlocks, light curtains) with diagnostic coverage suited to the required safety level.

Typically locatedMachine and cell control panels.

At a glance

PurdueLevel 1 (safety)
CategorySafety
Protocolscip-safety, profinet, ethernet-ip, umas
Talks toSafety I/O, Standard controller, Safety configuration tooling
Common vendorsRockwell Automation (GuardLogix), Siemens (S7-1500F / S7-1200F, PROFIsafe), Schneider Electric (Modicon M580 Safety), ABB (AC 500-S), Omron, Phoenix Contact

Why should I care?

Safety PLC sits at Level 1 (safety). Compromise here is not just a data problem — it changes what the physical process does or what operators can see and control.

Common security problems

  • Shared network with standard control traffic
  • Safety configuration tools on general-purpose laptops
  • Undocumented bypasses

If it is compromised

  • Machine guarding functions can be undermined
  • Personnel safety risk

What to monitor

  • Safety program signature changes
  • Bypass activation
  • Safety connection faults

How to defend it

  • Change control with engineering sign-off
  • Password/lock safety configuration
  • Alarm on signature change