F31806 — Encoder 1: Initialization error

F31806 tells you that the initialization of encoder 1 (Sensor Module Encoder 1) did not complete successfully. The drive stores in r0949, as a bit pattern, exactly which step of the initialization failed; on G130 and G150 the manual prints this value as the placeholder %1. One List Manual asks for the value to be read in binary, the other in hexadecimal — the bit assignments are the same in both. Depending on how the drive is configured, the same condition can also be output as an alarm or without any drive reaction.

• The encoder did not get through its initialization; the fault value in r0949 identifies the stage at which it failed.

1. Acknowledge the fault first — often this alone clears it.
2. If the fault comes back, read the bits of the fault value in r0949 and follow the steps that match.
3. Bits 2 ... 9 set: check the encoder power supply.
4. Bits 2 ... 14 set: check the cable belonging to the affected track.
5. Bit 15 and no other bit: check track R and the settings in p0404.
6. Bit 28 set: check the cable between the EnDat 2.2 converter and the measuring unit.
7. Bits 29 ... 31 set: replace the defective measuring unit.

• Bit 0, 1 — initialization was attempted while the motor was already turning and failed: the coarse and the fine position disagree, measured in encoder pulses/4.
• Bits 2 ... 9 — mid-voltage matching did not succeed for the track concerned: bit 2 track A, bit 3 track B, bit 4 the acceleration input, bit 5 safety track A, bit 6 safety track B, bit 7 track C, bit 8 track D, bit 9 track R.
• Bits 10 ... 14 — the mid-voltage spread between two tracks exceeds 0.5 V: bit 10 between A and B, bit 11 between C and D, bit 12 between safety A and safety B, bit 13 between A and safety B, bit 14 between B and safety A.
• Bit 15 — the standard deviation of the calculated mid-voltages is above 0.3 V.
• Bits 16 ... 18 — internal faults of the matching stage: bit 16 reading a register (CAFE), bit 17 writing a register (CAFE), bit 18 no mid-voltage matching available.
• Bit 19 — internal error, the ADC could not be accessed.
• Bit 20 — internal error, no zero crossover was found.
• Bit 28 — starting up the EnDat 2.2 measuring unit failed.
• Bits 29 ... 31 — a problem with the EnDat 2.2 measuring unit: bit 29 its data cannot be read out, bit 30 its EEPROM checksum is wrong, bit 31 its data is inconsistent.
• Hardware note — bits 0 and 1 are reported on hardware up to 6SL3055-0AA00-5*A0; bits 2 ... 20 apply from 6SL3055-0AA00-5*A1 onward.

• r0949 — holds the fault value for this message; read it bit by bit to see which stage of the encoder initialization failed.
• p0404 — the effective encoder configuration; when bit 15 is the only bit set, check the settings here.
• p0491 — the manual cross-references this parameter (motor encoder fault response ENCODER) because it governs how the drive responds to an encoder fault of this kind.

The first remedy is simply to acknowledge the fault. If it reappears immediately, the cause has not been removed — work through the bit-specific checks above (power supply, cable, p0404 settings or measuring unit) before acknowledging again.