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

Safety Integrated function
9.3 System features
Personal injury or device damage due to improper operations after the hardware and/or
software components change
After hardware and/or software components have been modified or replaced, all protective
equipment must be closed prior to system startup and drive activation; otherwise, personal
injury or device damage occur.
• No personnel is present within the danger zone.
• Before allowing anybody to re-enter the danger zone, you should test steady control
• To use Safety Integrated functions, you need to make sure that the system has
9.3.4

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 13849-1:2015. 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 PN 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 PN drive system is 5 × 10
Hardware fault tolerance (HFT)
The HFT value of SINAMICS V90 PN drive system is one. It means that the system can
handle one fault without brake down. SINAMICS V90 PN STO function is a subsystem from
type A, and only the discrete components are involved in the STO function.
9.3.5

Response time

Response time means the time from the control via terminals until the response actually
occurs. For 200 V variant servo drives, the STO response time in the worst case is 15 ms.
For 400 V variant servo drives, the STO response time in the worst case is 5 ms. The
response time of fault reaction functions is 2 s.
242
WARNING
response by briefly moving the drives in forward and reverse direction (+/–).
completely powered up.
per hour.
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SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 04/2020, A5E37208830-008