Sto Standards; Table 2-28: Sto Standards; Table 2-29: Sto Standards Data - Advantech Automation1 XC4 Hardware Manual

2.4. Safe Torque Off Input (STO)
2.4.1. STO Standards
Table 2-28 describes and specifies the safety requirements at the system level for the Safe Torque Off
(STO) feature of the XC4. This assumes that diagnostic testing is performed according to
and Table 2-29.
Table 2-28: STO Standards
Standard
EN/IEC 61800-5- 2:2016
EN/IEC 61508-1:2010
EN/IEC 61508-2:2010
EN ISO 13849-1:2015
EN/IEC 62061:2005 with Amendments
Table 2-29: STO Standards Data
Standard
EN ISO 13849-1:2015
EN ISO 13849-1:2015
EN/IEC 61508
EN/IEC 61508
62
Maximum Achievable Safety
SIL 3
SIL 3
SIL 3
Category 4, PL e
SIL 3
Value
MTTF > 1000 years,
D
DC 99%
AVG
Maximum PL e, Category 4
Lifetime = 20 years
No proof test required
Interval for manual STO test:
Once per year for SIL2/PL d/category 3
l
Once per three months for SIL3/PL e/category 3
l
Once per day for SIL3/PL e/category 4
l
SIL3
PFH < 3 FIT
SFF > 99%
XC4 Hardware Manual
Section 2.4.4.
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