246 Safe Torque off functionInclude the Safe torque off operation test described above in the routine maintenanceprogram of the machinery that the inverter runs.If any wiring or component change is needed after start up, or the parameters arerestored, follow the test given in section Acceptance test procedure on page 242.Use only ABB approved spare parts.Record all maintenance and proof test activities in the machine logbook. CompetenceThe maintenance and proof test activities of the safety function must be carried out bya competent person with adequate expertise and knowledge of the safety function aswell as functional safety, as required by IEC 61508-1 clause 6.Fault tracingThe indications given during the normal operation of the Safe torque off function areselected by drive parameter 31.22.The diagnostics of the Safe torque off function cross-compare the status of the twoSTO channels. In case the channels are not in the same state, a fault reactionfunction is performed and the drive trips on an “STO hardware failure” fault. Anattempt to use the STO in a non-redundant manner, for example activating only onechannel, will trigger the same reaction.See the drive firmware manual for the indications generated by the drive, and fordetails on directing fault and warning indications to an output on the control unit forexternal diagnostics.Any failures of the Safe torque off function must be reported to ABB.Safety data (SIL, PL)The 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 STOchannels are not used.FramesizeSIL/SILCLSC PL SFF PFH(T 1 = 20 a) PFD avg(T 1 = 2 a)PFD avg(T1 = 5 a)MTTFDDC Cat. HFT CCFLife-time(%) (1/h) (a) (%) (a)UN = 230 VR1 3 3 e >99 2.84E-09 2.37E-05 5.91E-05 10530 >90 3 1 80 20R2 3 3 e >99 2.84E-09 2.37E-05 5.91E-05 10529 >90 3 1 80 20R3 3 3 e >99 2.84E-09 2.37E-05 5.91E-05 10489 >90 3 1 80 20R4 3 3 e >99 2.89E-09 2.41E-05 6.02E-05 10442 >90 3 1 80 20R5 3 3 e >99 2.89E-09 2.41E-05 6.02E-05 10240 >90 3 1 80 20
