Safety dataThe safety data for the Safe torque off function is given below.Note:The safety data is calculated for redundant use, and does not apply if both STO channelsare not used.TM(a)CCFHFTSCCat.DC(%)MTTFD(a)PFDavg(T1 = 5 a)PFDavg(T1 = 2 a)PFH(T1 = 20 a)(1/h)SFF(%)PLSIL/SILCLFrame size2080133≥9093808.58E-053.44E-053.92E-09>99e3R6R72080133≥9087928.84E-053.69E-054.22E-09>99e3R8R92080133≥90175449.08E-053.63E-054.15E-0999.60e3R10R113AXD10000015777 K, 3AXD10000410558 D• The following temperature profile is used in safety value calculations:• 670 on/off cycles per year with ΔT = 71.66 °C• 1340 on/off cycles per year with ΔT = 61.66 °C• 30 on/off cycles per year with ΔT = 10.0 °C• 32 °C board temperature at 2.0% of time• 60 °C board temperature at 1.5% of time• 85 °C board temperature at 2.3% of time.• Relevant failure modes:• The STO trips spuriously (safe failure)• The STO does not activate when requested• A fault exclusion on the failure mode “short circuit on printed circuit board” has beenmade (EN 13849-2, table D.5). The analysis is based on an assumption that onefailure occurs at one time. No accumulated failures have been analyzed.• STO response times:• STO reaction time (shortest detectable break): 1 ms• STO response time: 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 13849-1CCFThe Safe torque off function 255
