6-5 Safe Torque Off 
AC30V series Variable Speed Drive 
Safety Specification 
 
As assessed to EN ISO13849-1 and EN61800-5-2 the AC30V has the following related safety values:- 
 
Criterion  Requirement  Value achieved 
SIL3 
For type A subsystems, HFT = 1: 
SFF ≥ 60% 
SFF = 99% 
SIL3  10
-7
 ≥ PFH ≥ 10
-8
  PFH = 2.3 x 10
-9
 
SIL Capability  -  3 
PLe  Category 3; PFH ≤ 4,29 x 10
-8
  PFH = 2.3 x 10
-9
 
PLe  30 years ≤ MTTFd < 100 years  MTTFd  = 100 years
1
 
PLe  DC = medium  DC = Medium 
Mission Time  20 years  20 years 
Fault Reaction Function  -  Latched STO
2
 
 
  
1
 EN ISO13849 limits MTTFd to 100 years. 
2
 A detected fault in the STO circuit causes STO to become active, and remain active until after a power cycle.