System Startup Diagnostics And Procedures - Siemens SIMATIC S5 Manual

S5-95U, SINEC L2
3.3.3

System Startup Diagnostics and Procedures

BF LED fault display
The BF (Bus Fault) LED lights up when
• the firmware of the S5-95U detects a fault, or
• if the communications processor integrated in the S5-95U is not activated.
BF LED
Lights up Communications
processor is not activated
Communications
processor has been
assigned the wrong
parameters
PLC remains in STOP
mode
LAN bus fault (can only
occur if the S5-95U is
connected to the LAN)
Note
If you start up the S5-95U with the default DB1, the communications processor will not
be activated and the BF LED will light up.
EWA 4NEB 812 6112-02
Table 3-1. Interpretation of the BF LED Display
Meaning
There is no SL2
parameter block in DB1
or it is enclosed by
comment characters (#)
SL2 parameter block in
DB1 contains errors
Fatal internal fault or
basic parameters are not
consistent over the entire
network, e.g. TLN
(station address) has
been allocated twice
(LAN bus fault
Start-Up, Tests, and Diagnostics
Cause
Table 3-10)
Corrected DB1 is
transferred to the PLC:
after STOP-RUN or
POWER OFF - POWER
ON on the PLC
after POWER OFF -
POWER ON on the PLC
after POWER OFF -
POWER ON on the PLC
3-7