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


Performance Level (PL) according to ISO 13849-1:2015


Probability of dangerous failure per hour (PFH)


Probability of dangerous failure on demand (PFDavg)


Hardware Fault Tolerance (HFT)


Reaction time

20 ms

Category (cat.)


Mean Time to Failure (MTTFd)


Diagnostic coverage (DCavg)



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


Allowed discrepancy between digital inputs

100 ms

De-activation time


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


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: