Safety specifications

System requirements

Required Firmware

  • v4.2.0 or higher

Supported Hardware

  • SOMANET Circulo 7
  • SOMANET Circulo 9

Technical specifications

Safety parameters  
Safety Integration level (SIL) according to IEC 61508:2010 SIL 3
Performance Level (PL) according to ISO 13849-1:2015 PL e cat. 3
Safe Failure Fraction (SFF) TBD
Probability of dangerous failure per hour (PFH d) TBD
Probability of dangerous failure on demand (PFD avg) TBD
Common Cause Failure (CCF) TBD
Hardware Fault Tolerance (HFT) 1
Reaction time 10 ms
De-activation time 10 ms
Mean Time to dangerous Failure (MTTF d) TBD
Diagnostic coverage (DC avg) TBD
HW-type Type A
Mission time T M TBD
Installation requirements  
Max. installation altitude 2000 m
Pollution Degree PD 2
Supported Motors 1 x 3-phase BLDC-Motor and 1 active brake


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.

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 0-60 VDC
Max. transient input voltage 80 VDC
Input voltage, logic 1 15-60 V
Input voltage, logic 0 0-5 V
Input current Max. 6 mA (@24 VDC)
Test pulse toleration (OSSD pulses) Max. 1 ms
Reverse voltage protected Yes
Allowed discrepancy between digital inputs

100 ms

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


This PWM controlled brake is configured by the same object as the regular brake.