Reliability Data For 12-Year Mission Time Test; Safe State; Safety Reaction Time; Considerations For Safety Ratings - Allen-Bradley PowerFlex 7000 Series User Manual

Chapter 2 Safety Concept

Safe State

Safety Reaction Time

Considerations for Safety
Ratings
12

Reliability Data for 12-year Mission Time Test

Attribute
PFH
SIL CL
PL
Category
MTTF
d
DC
avg
HFT
PTI (Proof Test Interval)
(1) STO data for all medium voltage drive frames.
The Safe State encompasses all operation that occurs outside of the other
monitoring and stopping behavior of the drive as defined as part of the normal
operation without the Safe Torque Off Option.
If a Functional Safety System Fault is detected, the safety option goes to the
Safe State. This includes faults related to integrity of hardware or firmware.
The safety reaction time is the amount of time from a safety-related event as
input to the system until the system is in the Safe State.
The safety reaction time from an input signal condition that triggers a safe
torque off to safe state reached is 1000 ms (maximum).
IMPORTANT An input signal condition that is present for less than the reaction time may
not result in the safety function being performed. A request of the safety
function for less than the reaction time may result in the detection of a fault.
The achievable safety rating of an application using the safety option installed
in PowerFlex 7000 drives is dependent upon many external factors.
For applications that rely on the immediate removal of power to the actuator,
resulting in an uncontrolled coast to stop, a safety rating up to and including
SIL CL3, PLe, and Cat. 3 can be achieved.
Rockwell Automation Publication 7000-UM203C-EN-P - September 2018
(1)
Value
2.26 E-8 1/hour
3
e
3
803 years
90%
1
12