Siemens SINUMERIK 840D sl Function Manual page 1014

Detailed description
2.4 Starting up the PLC program
2.4.9 Troubleshooting
This section describes problems which may occur, their causes and remedies and should be
read carefully before hardware is replaced.
Errors, cause/description and remedy
Serial
no.
error
informati
on
1
2
3
30
Errors Cause/description
No connection The MPI cable is not plugged in
via MPI to or is defective. Possibly, the
PLC. STEP 7 software is also not
correctly configured for the MPI
card.
PLC cannot A system data block SDB 0 has
be accessed been loaded with a modified MPI
in spite of address. This has caused an
PLC general MPI bus conflict due to dual
reset. assignment of addresses.
All four LEDs A system error has occurred in
on the PLC the PLC.
flash (DI Measures: The diagnostic buffer
disaster) on the PLC must be read to
analyze the system error in
detail. To access the buffer, the
PLC must be stopped (e.g., set
"PLC" switch to position 2). A
hardware reset must then be
performed. The diagnostic buffer
can then be read out with
STEP7. Relay the information
from the diagnostic buffer to the
Hotline / Development Service. A
general reset must be carried out
if requested after the hardware
RESET. The diagnostic buffer
can then be read with the PLC in
the Stop state.
To correct or avoid errors
Test: Create a link with the
programmer in the STEP7 editor by
means of connection "Direct_PLC". A
number of node addresses must be
displayed here. If they do not appear,
the MPI cable is defective/not plugged
in.
Disconnect all MPI cables to other
components. Create the link
"Direct_PLC" with the programmer.
Correct the MPI address.
Once the PLC program has been
RESET or reloaded, the system may
return to normal operation. Even in this
case, the content of the diagnostic
buffer should be sent to the
Development Office.
Basic logic functions: PLC Basic program powerline (P3 pl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0