Siemens Simatic S7-300 CPU 31xC Series - Page 181

Debugging functions, diagnostics and troubleshooting
10.3 Overview: Diagnostics
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
10-5
Error handling
Programming with foresight and, above all, knowledge and proper handling of diagnostic
tools puts you into an advantageous position in error situations:
• You can reduce the effects of errors.
• It makes it easier for you to locate errors (by programming error OBs, for example).
• You can limit downtimes.
Diagnostics with LED display
SIMATIC S7 hardware offers diagnostics with LEDs.
These LEDs are implemented in three colors:
LED color State of CPU
Green Regular operation.
Example: Power is on.
Yellow Non-regular operating status.
Example: Forcing is active.
Red Fault.
Example: Bus error
LED flashing Special event
Example: CPU memory reset
Two LEDs are used for Ethernet:
LED designation Color State Meaning
LINK Green Off No other device is connected with the integrated
PROFINET interface of the CPU.
On Another device (in most cases a switch) is connected to
the integrated PROFINET interface of the CPU, and the
physical connection is in place.
RX/TX Yellow Off No activity:
No data are transferred via the integrated PROFINET
interface of the CPU.
On Activity:
Data are transferred via the integrated PROFINET
interface of the CPU.
Note: The LED flickers when small data volumes are
transferred.
Reference
Notes on diagnostics of I/O modules capable of diagnostics are found in the relevant
Manual.