Safety Circuit / Restart Lock (STO)
Note
The safety relay as well as the emergency stop device have to be certificated as safety
devices of at least level SIL 3 to obtain safety level SIL 3 according to EN ISO 13849-1.
Note
In order to obtain the safety level SIL 3 according to EN ISO 13849-1, the circuit and the
layout have been dimensioned according to IEC 60664-1:2008-01. Supporting materi-
al according to IEC 60249 covered by a nonaging protective coat of lacquer according
to IEC 60664-3:2003-09 have been used. The conformity of standard have been tested
and approved by the TÜV-Nord CERT.
12.3
Requirements and Standards
The following parameters are achieved according to the safety case:
▶
according to EN ISO 13849-1:2008-12
– MTTFd: >100 years
– DC = 99%
– Category 4
– Performance Level e
▶
according to EN 61508-1:2010 and EN 61800-5-2:2014-06
– PFH = 0
– SFF = 100 % (if there are PFH values, then SFF<100%)
– HFT = 0
The safety concept K1 meets the requirements of SIL 3 according to the standards
named above.
Requirements according to DIN EN 61800-5-2:2014-06
When connected appropriately, the safety concept K1 does not supply any share of dan-
gerous, undetected errors in the safety chain for the function STO.
Thus the stop function 0+1 according to DIN EN 60204-1 is realized.
104
Drive System SD2M - Hardware Description 036228xxF
STO
function
acc. to
EN ISO
13849-1:2008-12,
DIN EN 62061:2005
SIL
3
not
possible
