What it means
A30502 appears as the alarm Power unit: DC link overvoltage
. It is raised when the power unit has detected overvoltage in the DC link on a pulse inhibit. The full entries for the S120, S150, G130, G150, G120 and G120XA describe the message with the same cause and remedy; the compact tables for the G120C and G115D list it under the short title 'DC link overvoltage', with the G120C table naming only the line-reactor check. The message value carries the alarm value, so the DC link voltage the message was raised with can be read out directly (see below).
Why it appears
- The device supply (connection) voltage is too high.
- The line reactor is incorrectly dimensioned.
What to check
- Check the device supply voltage; the entry points to p0210 (Drive unit line supply voltage) for this check.
- Check the dimensioning of the line reactor.
Reading the message value
- The manual prints the message value as %1 and gives the alarm value in r0949, to be interpreted as a decimal number.
- The alarm value is the DC link voltage, with 1 bit corresponding to 100 mV.
Parameters the manual names
- p0210 — Drive unit line supply voltage: the parameter the remedy names for the check of the device supply voltage.
- r0070 — the entries cross-reference this parameter for the alarm as the actual DC link voltage (the parameter chapter lists it as CO: Valve position voltage setpoint before inversion / U_set before inv); read it to observe the DC link voltage.
- r0949 — alarm value: for A30502 it holds the DC link voltage, read as a decimal number with 1 bit = 100 mV.
Acknowledging and restarting
No acknowledgment is required for this alarm: the drive takes no automatic protective action on it and there is nothing to reset at the operator panel. The task is the remedy itself — check the device supply voltage (p0210) and the dimensioning of the line reactor. The alarm value in r0949 shows the DC link voltage the message was raised with.
What differs between the drive families
Straight from the manuals' own fields — A30502 is not described identically everywhere.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | DC link overvoltage (4) | Power Module | SINAMICS S120, S150 List Manual · p. 2970 |
| G130, G150 | NONE | NONE | DC link overvoltage (4) | Power Module | SINAMICS G130, G150 List Manual · p. 1674 |
| G120 | NONE | NONE | DC link overvoltage (4) | — | SINAMICS G120 · p. 919 |
| G120XA | NONE | NONE | — | — | SINAMICS G120XA PN converter · p. 1164 |
| G120C | — | — | — | — | SINAMICS G120C Converters · p. 387 |
| G115D | — | — | — | — | SINAMICS G115D distributed drive · p. 396 |
The drives this code lives on
A30502 is described for G115D, G120, G120C, 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 A30502 mean?
It is the alarm 'Power unit: DC link overvoltage': the power unit has detected overvoltage in the DC link on a pulse inhibit. The alarm value in r0949 gives the DC link voltage, decoded as a decimal number with 1 bit = 100 mV.
How do I fix A30502 on a G120 or S120?
The remedy is the same on every family that prints it in full: check the device supply voltage (p0210) and check the dimensioning of the line reactor.
Does A30502 have to be acknowledged?
No. The drive takes no automatic protective action on this alarm and no acknowledgment or reset is required; what matters is removing the cause — the too-high supply voltage or the wrongly dimensioned line reactor.
Where can I read the DC link voltage for A30502?
In r0949, the alarm value, interpreted as a decimal number where 1 bit = 100 mV. The entries also cross-reference r0070 as the actual DC link voltage.
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 A30xxx group · SINAMICS manuals · Siemens manuals