ABB MicroFlex e190, User Manual, Page: 204 / 210

204 Appendix: Safe Torque Off (STO)
Technical data

STO safety relay type
General requirements EN 61508 and/or EN 61511 and/or
EN ISO 13849-1
Output requirements
No. of current paths 2 independent paths (one for each STO path)
Switching voltage capability 30 V DC per contact
Switching current capability 10 mA per contact per drive
Maximum switching delay
between contacts <200 ms
Internal supply/multiple
units
Maximum length of safety
circuit from operating contact
to most distant drive 30 m (98.4 ft)
Maximum number of drives in
circuit 16
External supply/multiple
units
External power supply 24 V DC +10% SELV
Current requirement 20 mA per connected drive
Example 1 Simple SIL3 approved safety relay
Type and manufacturer PSR-SCP- 24UC/ESP4/2X1/1X2 by Phoenix
Contacts
Approvals EN 954-1, cat 4; EN 61508, SIL3
Example 2 Programmable safety logic
Type and manufacturer PNOZ Multi M1p by Pilz
Approvals EN 954-1, cat 4; EN 61508, SIL3; and
EN ISO 13849-1, PL e