411, 611 & 325 OCU
User Manual
35
9M02-8999-A001-EN
10 Requirements to
Achieve PLd within a ‘System’
The 411, 611 and 325 OCUs meet a PLd rating for the Main Contactor control relays.
The Stop switch and all after is a CAT3 architecture with safety critical firmware, meeting ISO13849 performance
level d.
Additionally, all OCU motion functions can meet the same performance level if two switch elements are used to
operate a function, i.e. on a 325 both direction and speed switch inputs are combined into one control function, or
on a 411 or 611 two switch inputs (one enable one control) are combined.
The R10 and R17 MCUs have the option of Safety Relays for motion functions and if two of these are used for a
function, or one used as a motion enable and the other is placed in series, then a PLd performance level can also
be achieved in the MCU and hence the entire motion function can be at a PLd level.
