3 Terms, definitions and conventions

3.3 Abbreviations and symbols

Symbol	Definition
Binary	Symmetric Channel
Cyclic	Redundancy Check
Fail-safe	substitute Values
Human-machine	interface
Least	significant bit
Most	significant bit
Operator	Acknowledgment
OPC	UA PI
OPC	UA Platform Interface
Protocol	Data Unit
Bit	error probability
Platform	Interface
Performance	Level
Programmable	Logic Controller
Conditional	residual error probability
Process	Values
Safety	Application Program Interface
Safety	Communication Layer
Safety	Function Response Time
Safety	Integrity Level
Safety	PDU, Safety Protocol Data Unit
Safety	Parameter Interface
Safety	Trailer