Specifications of the safety functions

System requirements

Required Firmware

  • v4.2.0 or higher

Supported Hardware

  • SOMANET Node 2000 Safety (E revision or newer) *
  • SOMANET Node 1000 Safety (E revision or newer)
  • SOMANET Node 400 Safety (E revision or newer)

* External fuse at main supply (48 VDC) is required for drive 2000 dimensioned according to driven load.

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) 99.99 %
Probability of dangerous failure per hour (PFH d) 1.07*10 -10 /hour
Probability of dangerous failure on demand (PFD avg) 9.41*10 -6
Common Cause Failure (CCF) >65
Hardware Fault Tolerance (HFT) 1
Reaction time 10 ms
De-activation time 10 ms
Mean Time to dangerous Failure (MTTF d) 3035 years (capped to 100 years)
Diagnostic coverage (DC avg) 99%
HW-type Type A
Mission time T M 20 a
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 the Safety module shall be used only in Pollution Degree environments class PD1 or PD2 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.

Block diagram

Simplified block diagram of servo drive with Safety Module:


For details of the connectors please refer to: