Pilz PSSu H FS SN SD - Manual (Page 21)

Operation
Operating Manual PSSu H FS SN SD(­T)(­R)
1001451­EN­08 21
8.2.1 MBUS
The "MBUS" LED indicates the status of the FS and ST module bus.
Colour State Meaning
­ ­ ­ No modules present
Green FS and ST module bus are operating error­free
Red Operating status "Safe condition of all FS outputs on the
PSSu system" or
Unable to locate at least one module
(e.g. a module has been removed during operation, actual/
registered hardware does not match)
Operating status "FS module bus in a STOP condition with
error: Major FS error"