Probability Of Failure Of The Safety Function; Response Time - Siemens SINAMICS V90 Operating Instructions Manual

Safety Integrated function
8.3 System features
After hardware and/or software components have been modified or replaced, all protective
equipment must be closed prior to system startup and drive activation. Personnel shall not
be present within the danger zone.
Before allowing anybody to re-enter the danger zone, you should test steady control
response by briefly moving the drives in forward and reverse direction (+/–).
To observe during power on:
The Safety Integrated functions are only available and can only be selected after the
system has completely powered up.
8.3.4

Probability of failure of the safety function

Probability of failure per hour (PFH)
The probability of the failure of safety functions must be specified in the form of a PFH value
in accordance with IEC 61508, IEC 62061, and ISO 13849-1:2006. The PFH value of a
safety function depends on the safety concept of the drive unit and its hardware
configuration, as well as on the PFH values of other components used for this safety function.
Corresponding PFH values are provided for the SINAMICS V90 drive system, depending on
the hardware configuration (number of drives, control type, number of encoders used). The
various integrated safety functions are not differentiated.
The PFH value of SINAMICS V90 drive system is 5 × 10
Hardware fault tolerance (HFT)
The HFT value of SINAMICS V90 drive system is one. It means that the system can handle
one fault without brake down. SINAMICS V90 STO function is a subsystem from type A, and
only the discrete components are involved in the STO function.
8.3.5

Response time

Response time means the time from the control via terminals until the response actually
occurs. The worst response time for the STO function is 5 ms. The response time of fault
reaction functions is 2 s.
252
WARNING
per hour.
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SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 09/2016, A5E36037884-002