F31110 — Encoder 1: Serial communications error

Encoder 1 signals that the transfer of its serial communication protocol is disturbed: the exchange between the encoder and the internal or external evaluation module contains an error, so the drive does not receive a usable position value from this encoder. The drive writes the cause of the fault into r0949 as a binary value; each set bit identifies one specific failure of the transfer, and the remedy follows from that bit. The bit meanings on this page apply to an EnDat 2.1 encoder; for an EnDat 2.2 encoder the manual describes the significance of the fault value under F3x135 (x = 1, 2, 3). The same condition is not only raised as a fault — depending on the drive configuration it can also appear as an alarm (A) or as a message without reaction (N).

• The transfer of the serial communication protocol between the encoder and its evaluation module has an error; which part of the transfer failed is stored bit by bit in the fault value (r0949, interpreted binary).

1. Read the fault value in r0949 as a binary number and find the set bit; the measure depends on that bit.
2. Bit 0 set: encoder defect — F31111 may provide additional details.
3. Bit 1, 2 or 7 set: the encoder type is incorrect — replace the encoder or its cable.
4. Bit 3 set: treat as an EMC problem — attach the cable shield, and replace the encoder or its cable.
5. Bit 4 or 5 set: attach the cable shield (EMC), replace the encoder or its cable, and replace the Sensor Module.
6. Bit 6 set: update the Sensor Module firmware.
7. Bit 8 set: check the parameterization (p0429.2).
8. Bit 9 set: attach the cable shield (EMC), replace the encoder or its cable, and replace the Sensor Module.
9. Bit 10 set: check the parameterization (p0429.2, p0449).
10. Bit 11 set: check the parameterization (p0436).
11. Bit 12 set: check the parameterization (p0429.6).
12. Bit 13 set: check the data line.
13. Bit 14 set: the encoder type is incorrect — replace the encoder or its cable.

The drive enters the fault cause into r0949; interpret the value in binary:

• 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.

• r0949 — the fault value: read it as a binary number to see which bit triggered F31110 and which measure applies.
• p0429 — encoder SSI configuration: for this fault check index 2 (bit 8, protocol too long, and bit 10, frame error when reading twice) and index 6 (bit 12, signal level error during the monoflop time).
• p0449 — encoder SSI filler bits: check it together with p0429.2 when bit 10 is set.
• p0436 — encoder SSI parity bit: check it when bit 11 signals a parity error.

After the cause has been removed, acknowledge the fault — the drive accepts the acknowledgment only with pulse inhibit. Where the same condition is configured only as an alarm or as a message without reaction, nothing needs to be acknowledged.