What it means
A33401 is the zero mark monitoring alarm of Encoder 3: the drive has covered 1.5 times the parameterized zero mark distance without detecting a zero mark. The list manuals print the message as Encoder 3: Alarm threshold zero mark failed
and Encoder 3: Zero mark failed (alarm threshold exceeded)
; depending on how the drive is configured, the same condition can also be output as a fault (F) or with no reaction (N).
Why it appears
- 1.5 times the parameterized zero mark distance was exceeded without a zero mark being detected.
- The zero mark distance this monitoring evaluates is set in p0425 for a rotary encoder and in p0424 for a linear encoder.
What to check
- Check that the encoder cables are routed in compliance with EMC.
- Check the plug connections.
- Check the encoder type — the encoder must deliver equidistant zero marks.
- Adapt the parameter for the clearance between zero marks (p0425).
- Replace the encoder or the encoder cable.
Reading the message value
- The drive places the alarm value from r2124 in the message value; interpret it as a decimal number.
- The value is the number of increments after POWER ON or since the last zero mark that was detected.
- 4 increments correspond to 1 encoder pulse.
Parameters the manual names
- p0425 — sets the zero mark distance for a rotary encoder; this is the value to adapt so it matches the actual clearance between zero marks of the connected encoder.
- p0424 — sets the zero mark distance for a linear encoder; the zero mark monitoring evaluates this parameter instead of p0425 when Encoder 3 is linear.
- r2124 — holds the alarm value; read it here, interpreted as decimal, to see how many increments have elapsed after POWER ON or since the last detected zero mark.
Acknowledging and restarting
As an alarm, A33401 requires no acknowledgement. If the drive is configured to output the condition as a fault instead, the fault must be acknowledged IMMEDIATELY.
The same on every family
Every manual that describes A33401 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | Actual position/speed value incorrect or not available (11) | Encoder 3 | SINAMICS S120, S150 List Manual · p. 3152 |
| G130, G150 | NONE | NONE | Actual position/speed value incorrect or not available (11) | Encoder 3 | SINAMICS G130, G150 List Manual · p. 1824 |
The drives this code lives on
A33401 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 A33401 mean on a SINAMICS drive?
It is the zero mark monitoring alarm of Encoder 3: 1.5 times the parameterized zero mark distance (p0425 for a rotary, p0424 for a linear encoder) was covered without a zero mark being detected.
How do I clear A33401?
Check that the encoder cables are routed in compliance with EMC, check the plug connections, verify that the encoder delivers equidistant zero marks, adapt p0425, and replace the encoder or encoder cable if necessary. As an alarm the message itself needs no acknowledgement.
What is the alarm value of A33401?
The message value contains the alarm value from r2124, interpreted as a decimal number: the increments counted after POWER ON or since the last detected zero mark, where 4 increments equal 1 encoder pulse.
Does A33401 stop the drive?
No — as an alarm the drive takes no action and no acknowledgement is required. If the drive is configured to raise the same condition as a fault, it must be acknowledged IMMEDIATELY.
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 A33xxx group · SINAMICS manuals · Siemens manuals