Xenus Plus Compact STO Manual
16-01553 Rev 00
Page 17 of 31
Copley Controls
6.6.7 24V DC Power Supply
A constraint on the larger system is that the power supply used to provide the 24V control power to the drive
must be a SELV or PELV type.
6.6.8 AC Mains Over-Voltage Category
The AC mains supplying the drive must be limited to over-voltages of Category II. The relevant standards
assume AC mains with over-voltages per OVC III. An SPD or isolation transformer is required to
limit over-voltages to OVC II levels.
6.6.9 Wiring to the STO Inputs
Electrical connections to the STO inputs must meet the requirements for fault exclusions for short circuits
between conductors and short circuits between conductors and other conductive parts or earth or the
protective bonding conductor. Fault exclusion requirements are given in ISO 13849-2 and IEC 61800-5-2.
Toward this end, the STO cable connector is a crimp and poke type in order to meet the relevant fault
exclusions. The contacts and connector provide spacing that is greater than the minimum creepage and
clearance of 1.24 mm that is required for fault exclusion when considering the FMEDA (Failure Modes,
Effects, and Diagnostic Analysis) of the system.
6.6.10 Periodic Test Requirements
In order to meet the diagnostic coverage requirements for Cat. 3 PL d, the STO function must be checked at
least once per year. See section 9 for specific details.
