Probability Of Failure Of The Safety Function - Siemens Sinamics V90 Operating Instructions Manual

Safety Integrated function
8.3 System features
Personal injury or device damage deu to improper operations of the Emergency Stop
function
There is a personal injury or device damage if you use the Emergency Stop function
improperly. According to the standard EN 60204-1:2006, Emergency Stop function must
bring the machine to a standstill in accordance with STO.
• Make sure that, if you use the Emergency Stop function to shut down the machine, the
• When the safety function is deactivated, an automatic restart is permitted under certain
Personal injury or device damage deu 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
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 13849-1:2015. 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 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.
308
WARNING
machine is not allowed to restart automatically after EMERGENCY STOP.
circumstances depending on the risk analysis (except when Emergency Stop is reset).
For example, an automatic start is permitted when a protective door is closed.
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, 04/2019, A5E36037884-007