F33110 — Encoder 3: Serial communications error

F33110 is raised when the drive detects an error in the transfer of the serial communication protocol between Encoder 3 and the internal or external evaluation module — the actual position or speed value is therefore incorrect or not available. The fault value stored in r0949, interpreted in binary, identifies which of the bit-level problems occurred. Depending on how the drive is configured, the same condition can also be output as an alarm (A) or without any reaction (N).

• There is an error in the transfer of the serial communication protocol between the encoder and the internal or external evaluation module.
• Which of the bit-level conditions applies is shown by the fault value in r0949 (see the decoding below).

1. Read the fault value in r0949 and interpret it in binary; the set bit selects the appropriate action below.
2. Bit 0 set: the encoder signals a defect — fault F31111 may provide additional details.
3. Bit 1, 2, 7 or 14 set: incorrect encoder type — replace the encoder or the encoder cable.
4. Bit 3 set: EMC problem — connect the cable shield and replace the encoder or the encoder cable.
5. Bit 4, 5 or 9 set: EMC problem — connect the cable shield, replace the encoder or the encoder cable, and replace the Sensor Module.
6. Bit 6 set: update the Sensor Module firmware.
7. Bit 8 set: check parameterization (p0429.2).
8. Bit 10 set: check parameterization (p0429.2, p0449).
9. Bit 11 set: check parameterization (p0436).
10. Bit 12 set: check parameterization (p0429.6).
11. Bit 13 set: check the data line.
12. After the cause has been remedied, acknowledge the fault and restart the drive.

The drive writes the fault cause into r0949 as a binary value. For an EnDat 2.1 encoder, the bits have the following significance:

• Bit 0: Alarm bit in the position protocol.
• Bit 1: Incorrect quiescent level on the data line.
• Bit 2: Encoder does not respond (does not supply a start bit within 50 ms).
• Bit 3: CRC error: The checksum in the protocol from the encoder does not match the data.
• Bit 4: Encoder acknowledgment error: The encoder incorrectly understood the task (request) or cannot execute it.
• Bit 5: Internal error in the serial driver: An illegal mode command was requested.
• Bit 6: Timeout when cyclically reading.
• Bit 7: Timeout for the register communication.
• Bit 8: Protocol is too long (e.g. > 64 bits).
• Bit 9: Receive buffer overflow.
• Bit 10: Frame error when reading twice.
• Bit 11: Parity error.
• Bit 12: Data line signal level error during the monoflop time.
• Bit 13: Data line incorrect.
• Bit 14: Fault for the register communication.
• Bit 15: Internal communication error.

Note: for an EnDat 2.2 encoder, the significance of the fault value is described for F3x135 (x = 1, 2, 3).

• r0949 — fault value: read the fault cause here and interpret it in binary to find the bit that triggered F33110.
• p0429 (Encoder SSI configuration): check p0429.2 when bit 8 or bit 10 is set, and p0429.6 when bit 12 is set.
• p0449 (Encoder SSI number of bits filler bits): check it when bit 10 is set.
• p0436 (Encoder SSI parity bit): check it when bit 11 (parity error) is set.

Acknowledge the fault with pulses inhibited: put the drive into a pulse-inhibited state, acknowledge the message, and only then re-enable the pulses so the drive can restart. Where the drive is configured to output the condition as an alarm or without any reaction, no acknowledgment is required.