Festo — CMMT-AS-...-S1 — 2021-04d
Technical data
35
Safety reference data for the safety sub-function SBC
Circuitry
Two brakes
1)
with SBA evalua-
tion
2)
One brake
3)
Without SBA eval-
uation
Probability of dan-
gerous failure per hour
in accordance with
EN 61508, PFH
[1/h]
3.00 x 10
–10
9.00 x 10
–8
Mean time to
dangerous failure
in accordance with
EN ISO 13849-1, MTTF
d
[a]
1400
950
Average diagnostic
coverage in accordance
with EN ISO 13849-1,
DC
AVG
[%]
93
–
Operating life (mission
time) in accordance
with EN ISO 13849-1,
T
M
[a]
20
Safe failure fraction
SFF in accordance with
EN 61508
[%]
99
87
Hardware fault toler-
ance in accordance
with EN 61508, HFT
1
0
Common cause factor
for dangerous unde-
tected failures
β
in accordance with
EN 61508
[%]
5
Classification in
accordance with
EN 61508
Type A
1) One brake connected to BR+/BR− and a second brake connected to BR-EXT; 2-channel wiring and request via #SBC-A and #SBC-B.
2) Safety sub-function monitored by the safety controller via the SBA diagnostic output at least once every 24 h.
3) Brake connected either to BR+/BR− or to BR-EXT; 1-channel request via the safety controller using #SBC-A and #SBC-B; both inputs
must be bridged externally.
Tab. 17: Safety reference data for the safety sub-function SBC
Remarks
