Beckhoff TwinSAFE EJ Series - Safety Parameters

EJ1957
EJ19xx and EJ29xx32 Version: 1.2.0
8.4 Safety parameters
Characteristic numbers EJ1957
Lifetime [a] 20
Proof test interval [a] not required
1)
PFH
D
4.43E-09
%SIL3 of PFH
D
4.4%
PFD
avg
5.0E-05
%SIL3 of PFD
avg
5.0%
MTTF
D
1731a
DC 98.4% (CAT4)
Performance Level PLe
Category 4
HFT 1
Classification element
2)
Type B
1. Special proof tests are not required during the entire service life of the EJ1957 EtherCAT module.
2. Classification according to IEC61508-2:2010 (see chapters 7.4.4.1.2 and 7.4.4.1.3)
The EJ1957 EtherCAT module can be used for fail-safe applications within the meaning of IEC62061 and
IEC61508:2010 up to SIL3 and ENISO13849-1:2015 up to PLe (Cat4).
Further information on calculating or estimating the MTTF
D
value from the PFH
D
value can be found in the
TwinSAFE application manual 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.