- Frames R3…R8: 2 ms (typical), 5 ms (maximum)• Fault detection time: Channels in different states for longer than 200 ms• Fault reaction time: Fault detection time + 10 ms• Indication delays:• STO fault indication (parameter 31.22) delay: < 500 ms• STO warning indication (parameter 31.22) delay: < 1000 ms￭ AbbreviationsDescriptionReferenceAbbr.Classification of the safety-related parts of a control system in respectof their resistance to faults and their subsequent behavior in the faultcondition, and which is achieved by the structural arrangement of theparts, fault detection and/or by their reliability. The categories are: B,1, 2, 3 and 4.EN ISO 13849-1Cat.Common cause failure (%)EN ISO 13849-1CCFDiagnostic coverageEN ISO 13849-1DCHardware fault toleranceIEC 61508HFTMean time to dangerous failure: (Total number of life units) / (Numberof dangerous, undetected failures) during a particular measurementinterval under stated conditionsEN ISO 13849-1MTTFDAverage probability of dangerous failure on demand, that is, meanunavailability of a safety-related system to perform the specified safetyfunction when a demand occursIEC 61508PFDavgAverage frequency of dangerous failures per hour, that is, averagefrequency of a dangerous failure of a safety related system to performthe specified safety function over a given period of timeIEC 61508PFHPerformance level. Levels a…e correspond to SILEN ISO 13849-1PLSystematic capabilityIEC 61508SCSafe failure fraction (%)IEC 61508SFFSafety integrity level (1…3)IEC 61508SILMaximum SIL (level 1…3) that can be claimed for a safety functionor subsystemIEC/EN 62061SILCLSafe torque offIEC/EN 61800-5-2STOProof test interval. T1 is a parameter used to define the probabilisticfailure rate (PFH or PFD) for the safety function or subsystem. Per-forming a proof test at a maximum interval of T1 is required to keepthe SIL capability valid. The same interval must be followed to keepthe PL capability (EN ISO 13849) valid.IEC 61508-6T1See also section Maintenance.Mission time: the period of time covering the intended use of the safetyfunction/device. After the mission time elapses, the safety device mustbe replaced. Note that any TM values given cannot be regarded as aguarantee or warranty.EN ISO 13849-1TMThe Safe torque off function 161
