What it means
N01621, titled "SI P1 (CU): Safe Stop 1 active" in the manuals, is a message without a reaction from the Safety Integrated (SI) monitoring: the drive reports that the "Safe Stop 1" (SS1) function has been selected on the Control Unit (CU) and is active. SS1 corresponds to Stop Category 1 acc. to EN60204. The manual is explicit about the effect of the message: This message does not result in a safety stop response.
Depending on how the drive is configured, the same condition can also be signalled as a fault or as an alarm. The code is described for the SINAMICS G130, G150, S120 and S150 families.
Why it appears
- The Safety Integrated "Safe Stop 1" (SS1) function has been selected on the Control Unit (CU) and is active. This state is what the message reports; the manuals name no other cause, and the G130/G150 and S120/S150 entries describe it identically.
What to check
- No remedy is necessary — the manuals state this explicitly for this code. The message reports the active SS1 state and does not result in a safety stop response, so there is nothing to check, correct or replace.
Acknowledging and restarting
No acknowledgement is required for this message: it reports the live state "SS1 selected and active on the Control Unit" and stands for as long as that condition holds. If the drive's configuration raises the same condition as a fault instead, the drive is stopped with OFF3 and the fault is then acknowledged immediately (POWER ON). Signalled as an alarm, the condition likewise needs no acknowledgement.
The same on every family
Every manual that describes N01621 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| G130, G150 | NONE | NONE | Safety monitoring channel has identified an error (10) | Control Unit (CU) | SINAMICS G130, G150 List Manual · p. 1431 |
| S120, S150 | NONE | NONE | Safety monitoring channel has identified an error (10) | Control Unit (CU) | SINAMICS S120, S150 List Manual · p. 2626 |
The drives this code lives on
N01621 is described for G130, G150, S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does N01621 "SI P1 (CU): Safe Stop 1 active" mean on a SINAMICS drive?
It reports that the Safety Integrated Safe Stop 1 (SS1) function has been selected on the Control Unit (CU) and is active. SS1 corresponds to Stop Category 1 acc. to EN60204.
Does N01621 stop the drive or trigger a safety response?
No. The manual states that this message does not result in a safety stop response — it only reports that SS1 is currently active.
How do I acknowledge or reset N01621?
No acknowledgement and no remedy are necessary. If your configuration raises the same condition as a fault, the drive stops with OFF3 and the fault is acknowledged immediately (POWER ON).
Which SINAMICS drives can issue N01621?
The code is described for SINAMICS G130, G150, S120 and S150; it is always tied to the Control Unit.
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 N01xxx group · SINAMICS manuals · Siemens manuals