BECKHOFF TwinSAFE - Manual (Page 123)

Circuit examples
Application Guide TwinSAFE 121
2.20.1 Parameters of the safe input and output terminals
EL1904 (applies to all EL1904 used)
Parameter Value
Sensor test channel 1 active Yes
Sensor test channel 2 active Yes
Sensor test channel 3 active Yes
Sensor test channel 4 active Yes
Logic channel 1 and 2 Single Logic
Logic channel 3 and 4 Single Logic
EL2904
Parameter Value
Current measurement active Yes
Output test pulses active Yes
2.20.2 Block formation and safety loops
2.20.2.1 Block 1
2.20.3 Calculation
2.20.3.1 PFH / MTTF
d
/B10
d
– values
Component Value
EL1904 – PFH 1.11E-09
EL2904 – PFH 1.25E-09
EL6900 – PFH 1.03E-09
AX5801 – B10d 780,000
S1 – B10
d
100,000
Days of operation (d
op
) 230
Hours of operation / day (h
op
) 8
Cycle time (minutes) (T
cycle
) 60 (1x per hour)
Lifetime (T1) 20 years = 175200 hours
EL1904 EL6900 EL1904 EL6900 S1
EL2904 AX5801 EL2904 AX5801 EL2904 AX5801 EL2904 AX5801
EL2904
EL2904 AX5801 EL2904 AX5801 EL2904 AX5801 EL2904 AX5801