Pilz PSSu H PLC1 FS SN SD - Manual (Page 22)

Operation
Operating Manual PSSu H PLC1 FS SN SD(­T)(­R)
21939­EN­10 22
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"