What it means
A05066 is raised on the S120 and S150 infeeds when, in a parallel connection, the voltages that the individual Voltage Sensing Modules (VSM) measure drift apart by more than the alarm threshold stored in p7324. The alarm value the drive writes to r2124 (to be read as a decimal number) names the pair of VSM voltages that deviates. Depending on the drive configuration, the same condition can also be output as a fault (F) or without any reaction (N).
Why it appears
- In the parallel connection, the individual voltages of the Voltage Sensing Modules (VSM) deviate from one another by more than the alarm threshold stored in p7324.
What to check
- Read the alarm value in r2124 as a decimal number to see which pair of VSM voltages is deviating.
- Check the alarm threshold in p7324 and adapt it if required.
- Inspect the connecting cables — loose contacts there can produce voltage spikes.
- Check the line connections, the line circuit breaker and the bypass contactors.
- Check the filter reactors and the filter capacitances: every parallel line filter must be of the same type, and none of the reactors or capacitors may be faulty.
- If a VSM and its power unit turn out to be faulty, deactivate both via p7001, or replace them if required.
Reading the message value
- The message value is a placeholder for the alarm value, which the drive stores in r2124; interpret it as a decimal number.
- 1: VSM voltage u1 - u2.
- 2: VSM voltage u2 - u3.
Parameters the manual names
- p7324 — the alarm threshold for the VSM voltage asymmetry; compare the measured deviation against it and adapt it if the limit does not suit the plant.
- r2124 — holds the alarm value for this message; read it as a decimal number to identify which VSM voltage pair deviates.
- p7001 — enables the power units of the circuit; use it to deactivate the power unit belonging to a faulty VSM.
Acknowledging and restarting
As an alarm, A05066 needs no acknowledgement; the practical task is to find and eliminate the asymmetry, since the message only signals the deviation. If the drive is configured to output the same condition as a fault instead, acknowledge that fault IMMEDIATELY once the cause has been removed.
The same on every family
Every manual that describes A05066 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | Infeed faulted (13) | Voltage Sensing Module (VSM) | SINAMICS S120, S150 List Manual · p. 2752 |
The drives this code lives on
A05066 is described for S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does alarm A05066 on a SINAMICS S120 or S150 mean?
In a parallel connection, the voltages measured by the individual Voltage Sensing Modules (VSM) differ by more than the alarm threshold set in p7324. The alarm value in r2124 shows which voltage pair is affected.
How can I see which VSM voltages are asymmetric?
Read the alarm value in r2124 as a decimal number: 1 means VSM voltage u1 - u2, 2 means VSM voltage u2 - u3.
Does A05066 shut the drive down or need a reset?
As an alarm it only reports the asymmetry, so there is no fault reset to perform. A reset only comes into play when the configuration issues the same condition as a fault, which is then acknowledged IMMEDIATELY.
Which parameters belong to A05066?
p7324 sets the alarm threshold for the VSM voltage asymmetry, r2124 holds the alarm value naming the deviating voltage pair, and p7001 enables the circuit's power units so a faulty one can be deactivated.
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 A05xxx group · SINAMICS manuals · Siemens manuals