Safety Parameters - Beckhoff AX8-1 Series Documentation

4.4

Safety parameters

Safety functions STO, SS1
Characteristic numbers
Lifetime [a]
Proof test interval [a]
PFH
D
%SIL3 of PFH
D
PFD
avg
%SIL3 of PFD
avg
MTTF
D
DC
SFF
Performance level
Category
HFT
2)
Classification element
1. Special proof tests are not required during the entire service life of the AX8911 TwinSAFE drive option
card.
2. Classification according to IEC 61508-2:2010 (see chapters 7.4.4.1.2 and 7.4.4.1.3)
The AX8911 TwinSAFE drive option card can be used for safety-related applications within the meaning of
IEC 61508:2010 up to SIL3, EN 62061:2005/A1:2013/A2:2015 up to SILCL3 and EN ISO 13849-1:2015 up
to PL e (Cat.4).
Further information on calculating or estimating the MTTF
TwinSAFE application guide or in EN ISO 13849-1:2015, Table K.1.
In terms of safety-related parameters, the Safety-over-EtherCAT communication is already considered with
1% of SIL3 according to the protocol specification.
Safe Motion functions SS2, SOS, SLS, SLP
The safety parameters for the Safe Motion functions are inserted here as soon as the AX8xxx-x2xx devices
with AX891x safety option card are enabled.
AX8911 - TwinSAFE Drive Option
AX8911 - STO, SS1 (AX8xxx-x1xx)
20
1)
not required
3.04E-09
3% of SIL3
9.20E-05
9% of SIL3
high
high, 99.5%
>99%
PL e
4
1
Type B
value from the PFH
D
Version: 1.0.0
Product description
value can be found in the
D
15