What it means
The alarm text is Writing to RAM disk unsuccessful
: a write access to the internal RAM disk of the Control Unit (CU) was unsuccessful. The manuals describe this alarm for the G120, G120XA, G130, G150, S120 and S150 Control Units. The drive takes no automatic reaction to it and the alarm does not have to be acknowledged — it is put right by a parameter change rather than by a reset or restart.
Why it appears
- The Control Unit (CU) attempted a write access to its internal RAM disk and the write access failed. This is the single cause the manuals list; they name no other.
What to check
- Adapt the file size of the system logbook so that it matches the internal RAM disk — set it with p9930 (System logbook activation / SYSLOG activation).
Parameters the manual names
- p9930 — System logbook activation (SYSLOG activation): the parameter the remedy for A01020 works with; use it to adapt the file size of the system logbook to the internal RAM disk.
Acknowledging and restarting
No acknowledgement is required for this alarm. The remedy is the p9930 change described above; the manuals describe no further reset or restart step.
What differs between the drive families
Straight from the manuals' own fields — A01020 is not described identically everywhere.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| G130, G150 | NONE | NONE | Hardware/software error (1) | Control Unit (CU) | SINAMICS G130, G150 List Manual · p. 1375 |
| S120, S150 | NONE | NONE | Hardware/software error (1) | Control Unit (CU) | SINAMICS S120, S150 List Manual · p. 2561 |
| G120 | NONE | NONE | Hardware/software error (1) | — | SINAMICS G120 · p. 822 |
| G120XA | NONE | NONE | — | — | SINAMICS G120XA PN converter · p. 1100 |
The drives this code lives on
A01020 is described for G120, G120XA, G130, G150, S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does SINAMICS alarm A01020 “Writing to RAM disk unsuccessful” mean?
It means that a write access to the internal RAM disk of the Control Unit (CU) was unsuccessful. The drive takes no automatic reaction and the alarm needs no acknowledgement.
How do I clear A01020 on a SINAMICS drive?
Adapt the file size of the system logbook to the internal RAM disk using p9930 (System logbook activation). That is the only remedy the manuals give; no acknowledgement is needed.
Which parameter is linked to alarm A01020?
p9930 — System logbook activation (SYSLOG activation). It is the parameter the manuals name for adapting the system logbook file size to the internal RAM disk.
Does A01020 also apply to my G120 or S120?
Yes — the manuals describe A01020 the same way for the G120, G120XA, G130, G150, S120 and S150 Control Units.
Codes next to this one
Source
Written from Siemens' own List Manuals and operating instructions; every number, designation and parameter on this page is checked against them before publication.
All SINAMICS codes: fault and alarm codes · the A01xxx group · SINAMICS manuals · Siemens manuals