What it means
A08751 (CAN: Telegram loss) reports that the CAN controller has lost a receive message — a telegram that the controller was supposed to receive on the CAN interface did not arrive. The drive signals this as an alarm and takes no protective action of its own; depending on how the drive is configured, the very same condition can also be signaled without any reaction. No acknowledgment is needed to clear it.
Why it appears
- The CAN controller has lost a receive message (telegram). All manual entries state this same single cause and print no deeper underlying causes for the alarm.
What to check
- Where the drive supplies a message value for this alarm, read the alarm value in r2124 — interpret it as a decimal number — to identify the hardware channel in the CAN controller whose receive message was lost (see the decoding below).
- Adjust the cycle times of the receive messages: the remedy printed for this alarm is to increase the cycle times of the received messages; one manual words the same remedy the other way round, as reducing the cycle times of the receive messages.
- If the drive communicates via CANopen, reduce the sampling time p8848 (IF2 PZD sampling time).
Reading the message value
- One entry prints a message value for this alarm; there the drive writes the alarm value, which is stored in r2124 and must be interpreted as a decimal number. It identifies the hardware channel in the CAN controller:
- 0: firmware version < 5.2 (no reference to the original hardware channel)
- 1: NMT command message
- 2: SYNC message
- 3: NMT error control message
- 7 ... 31: RPDO message
- 32: SDO message
- The remaining entries print no message value for this alarm.
Parameters the manual names
- r2124 — alarm value: read it here, interpreted as a decimal number, to identify the hardware channel in the CAN controller whose receive message was lost.
- p8848 — IF2 PZD sampling time: reduce this sampling time as the remedy when the drive communicates via CANopen.
Acknowledging and restarting
This alarm requires no acknowledgment. If it keeps recurring, work through the remedies above: increase the cycle times of the received messages and, on CANopen, reduce the sampling time in p8848.
What differs between the drive families
Straight from the manuals' own fields — A08751 is not described identically everywhere.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | Communication error to the higher-level control system (9) | None | SINAMICS S120, S150 List Manual · p. 2927 |
| G130, G150 | NONE | NONE | Communication error to the higher-level control system (9) | None | SINAMICS G130, G150 List Manual · p. 1641 |
| G120 | NONE | NONE | Communication error to the higher-level control system (9) | — | SINAMICS G120 · p. 900 |
The drives this code lives on
A08751 is described for G120, G130, G150, S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does A08751 CAN: Telegram loss mean?
The CAN controller has lost a receive message — a telegram it expected did not arrive. The drive only signals this as an alarm: it takes no protective reaction and the alarm needs no acknowledgment.
How do I fix alarm A08751?
Increase the cycle times of the received messages and, if the drive communicates via CANopen, reduce the sampling time p8848 (IF2 PZD sampling time). One manual prints the first remedy with the opposite wording, as reducing the cycle times of the receive messages.
What is the alarm value of A08751?
Where the manual decodes it, the alarm value is stored in r2124 and is interpreted as a decimal number identifying the hardware channel in the CAN controller: 0 firmware version < 5.2, 1 NMT command message, 2 SYNC message, 3 NMT error control message, 7 ... 31 RPDO message, 32 SDO message.
Does A08751 stop the drive or need a reset?
No. The alarm is issued without any protective reaction and requires no acknowledgment; depending on the drive configuration, the same condition can also be signaled without any reaction at all.
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 A08xxx group · SINAMICS manuals · Siemens manuals