Functional Safety

Functional safety is the discipline of proving that a protection system will do its job when it is needed: shut a plant down, stop a drive, trip on a gas alarm. Industry standards such as IEC 61508 and IEC 61511 set out how to measure that, using Safety Integrity Levels, or SILs. These three tools bring parts of that work into the browser. They are free and run in the browser. They are educational tools, not a substitute for a formal safety analysis, and the pages say so.

SIF Builder works at the level of a whole safety instrumented function. You assemble a loop from real manufacturer components (Rockwell, Siemens, Pilz, IFM, Turck and others), set the diagnostics on an interactive wiring diagram, and watch PFDavg or PFH and the resulting SIL change as you go. It supports both low-demand and high or continuous-demand modes.

FMEDA Workbench goes one level down, to individual electronic parts. You analyse failure modes, calculate the safe failure fraction and diagnostic coverage, and check them against the architectural constraints in IEC 61508-2. When you are done, you can export the result to SIF Builder, so the two together cover the verification chain from component to loop. Failure rate data comes from public sources such as SN 29500 and FMD-91, and the failure mode distributions are textbook defaults you should review for your own application.

Leaky Feeder Network Tool is the different one. It is for underground mines, where radio communication underpins safety. You draw a network of cable segments, amplifiers, splitters and couplers. Length Mode shows cable run utilisation for electricians, while Signal Mode shows dB signal budgets for RF technicians, so over-length runs and weak signals show up before anyone goes underground. It works offline as a PWA and keeps multiple projects.

Start with SIF Builder if you want to see how a SIL target is built up, FMEDA Workbench if you want to know where the numbers come from, and the leaky feeder tool if you work with mine communications.