Safety specifications

System requirements

Required Firmware

  • v4.2.0 or higher

Technical specifications

Safety parameters  
Safety Integration level (SIL) according to IEC 61508-1:2010 3
Performance Level (PL) according to ISO 13849-1:2015 e
Probability of dangerous failure per hour (PFH) TBD
Probability of dangerous failure on demand (PFDavg) TBD
Hardware Fault Tolerance (HFT) 1
Reaction time 20 ms
Category (cat.) 3
Mean Time to Failure (MTTFd) TBD
Diagnostic coverage (DCavg) TBD
HW-type Type A
Max. installation altitude 2000 m
Safe digital inputs (STO-SBC input)  
Number of digital inputs 2 (dual-channel safety input for activating STO-SBC function)
Digital input type according to IEC61131-2:2007 Type 1
Voltage range 0-30 VDC
Max. peak input voltage. 60 VDC
Input voltage, logic 1 15-30 V
Input voltage, logic 0 0-5 V
Galvanic isolation 2 kV Isolation voltage
Input current Max. 6 mA (@24 VDC)
Test pulse toleration (OSSD output pulses) Max. 1 ms
Reverse voltage protected Yes
Allowed discrepancy between digital inputs

100 ms

De-activation time TBD
Safe brake output (SBC)  
Number of digital outputs 2 (dual-channel safety output for one brake system)
Max. output voltage Servo drive main power supply (48 VDC)
Min. output voltage 0 V
Max. current. 1 A
Max. peak current. 4 A
Digital output (STO-SBC diagnostic output)  
Galvanic isolation 2 kV Isolation voltage
Max. current 100 mA
Max. continuous voltage across the output 27 V
Max. peak voltage across the output 35 V
Reverse voltage protected Yes
Max. delay after STO-SBC activation 50 ms


Servo drives including STO-SBC module shall be used only in Pollution Degree environments class PD 2 according to IEC 61800-5-1: During normal operation only non-conductive pollution may occur, temporarily occurring conductivity caused by condensation may only be expected when the servo drive is out of operation.

Block diagram

Simplified block diagram of the safety logic: