Technical data

6.9 Safety function STO
A frequently required application task is the protection of personnel against the restarting
of drives. The S300 servo amplifier offers, even in the basic version, a single channel
STO function (Safe Torque Off) that can be used as a personnel safe restart lock.
The safety function STO can be operated from a safe external control (semiconductor
output or driven contact).
The safetys concept is certified. The safety circuit concept for realizing the safety function
"Safe Torque Off" in the servo amplifiers S300 is suited for SIL CL 2 according to IEC
62061 and PLd according to ISO 13849-1.
Advantages of the restart lock STO :
— the DC bus link remains charged up, since the mains supply line remains active
— only low voltages are switched, so there is no contact wear
— very little wiring is required
6.9.1 Safety characteristic data
The subsystems (servo amplifiers) are totally described for safety technics with the
characteristic data SIL CL, PFH
D
and SFF.
Device Operation mode
EN
13849-1
EN 62061
PFH
D
[1/h]
SFF
[%]
MTTF
d
[Year]
STO-Enable STO single channel PLd SIL CL 2 0 100 311
S300 Instructions Manual 35
Kollmorgen 09/2011 Technical description