Interface Modules - Siemens S5-135U/155U System Manual

CPUs, Memory Cards, Memory Submodules, Interface Submodules
Fault LEDs SI1
LEDs SI1 and SI2 indicate faults in communication via interfaces SI1
and SI2
and SI2:
LED SI1
5-10
LED SI2 Cause
on on Communication is not possible at both interfaces.
Internal fault.
on off SI1:
No communication possible.
Internal fault.
SI2:
Interface is initialized and ready.
LED SI2 is always off if no interface module is
inserted.
off on SI1:
Interface is initialized and ready.
SI2:
No communication possible. Wrong module
inserted or internal fault.
off off Both interfaces are initialized and ready.
LED SI2 is always off if no interface module is
inserted.
System Manual
C79000-G8576-C199-06