3.2 Symbols and abbreviated terms
For the purposes of this document, the following symbols and abbreviated terms apply.
3.2.1 Abbreviated terms from IEC 61784-3
| CRC | Cyclic Redundancy Check | |
| PDU | Protocol Data Unit | [ISO/IEC 7498‑1] |
| PL | Performance Level | [ISO 13849‑1] |
| PLC | Programmable Logic Controller | |
| SCL | Safety Communication Layer | |
| SIL | safety integrity level | [IEC 61508‑4] |
| SPDU | Safety PDU, Safety Protocol Data Unit | |
3.2.2 Additional symbols and abbreviated terms
3.2.2.1 Abbreviated terms
| FSV | Fail-safe substitute Values | |
| HMI | Human-machine interface | |
| ID | Identifier | |
| LSB | Least significant bit | |
| MNR | MonitoringNumber | |
| MSB | Most significant bit | |
| OA | Operator Acknowledgment | |
| OPC UA PI | OPC UA Platform Interface | |
| PI | Platform Interface | |
| PV | Process Values | |
| SAPI | Safety Application Program Interface | |
| SFRT | Safety Function Response Time | |
| SPI | Safety Parameter Interface | |
| STrailer | Safety Trailer | |
| TRA | threat and risk analysis | |
3.2.2.2 Symbols
| p | Bit error probability | |
| Pre,cond | Conditional residual error probability | |