Siemens SINAMICS S120 Installation And Start-Up Manual page 220

Diagnosis
Messages – faults and alarms
Fault buffer
Faults which occur are entered in the fault buffer as follows:
Fig. 6-13
Properties of the fault buffer:
S A new fault incident encompasses one or more faults and is entered in "Current
fault incident".
S The entries are arranged in the buffer according to the time at which they
occurred.
S If a new fault incident occurs, the fault buffer is reorganized. The history is
recorded in "Acknowledged fault incident" 1 to 7.
S If the cause of at least one fault in "Current fault incident" is remedied and
acknowledged, the fault buffer is reorganized. The faults that have not been
remedied remain in "Current fault incident".
S If "Current fault incident" contains eight faults and a new fault occurs, the fault
in the parameters in index 7 is overwritten by the new fault.
S r0944 is incremented each time the fault buffer changes.
6-220
Structure of fault buffer
SINAMICS S120 Installation and Start-Up Manual, 12/04 Edition
E Siemens AG, 2004. All rights reserved