F31111 — Encoder 1: Absolute encoder internal error

F31111 is raised when Encoder 1 — the connected absolute encoder — signals an internal error. The encoder sets fault bits in its own error word (The encoder error word provides detailed information (error bit)), and the drive forwards this word as the fault value. The manuals print the message as Encoder 1: Absolute encoder internal error and as Encoder 1: Encoder signals an internal error (detailed information). Depending on the drive configuration, the same condition can also be output as an alarm or with no reaction.

• The connected encoder reports an internal error: it sets one or more fault bits in its own error word, and the drive raises this fault and stores that word as the fault value.
• Which internal condition is present is not fixed — it is read from the fault value bits (lighting system, signal amplitude, position value, encoder power supply, battery), as decoded below.

1. Check p0404.8 first. With p0404.8 = 0 the fault value is for internal Siemens troubleshooting. With p0404.8 = 1, read the fault value in r0949 and interpret it binary as yyyyxxxx hex: xxxx is the fault cause, yyyy the supplementary information.
2. For yyyy = 0, act according to the set bit. Bits 0, 1, 2 and 5 mean the encoder is defective: replace the encoder; where the motor encoder has a direct DRIVE-CLiQ socket, replace the motor.
3. Bits 3 and 4 indicate a 5 V power supply voltage fault. When using an SMC: check the plug-in cable between the encoder and the SMC or replace the SMC. Where a motor encoder with a direct DRIVE-CLiQ connection (bit 3) or a motor with DRIVE-CLiQ (bit 4) is used: replace the motor.
4. Bit 6 set: the battery must be changed — this applies only to encoders with battery back-up.
5. For yyyy = 1: the encoder is defective; replace the encoder.

• The message value is: Fault cause: %1 bin, additional information: %2 — the drive stores the fault cause and additional information for this fault.
• With p0404.8 = 0, the fault value is for internal Siemens troubleshooting.
• With p0404.8 = 1, r0949 is interpreted binary as yyyyxxxx hex: yyyy = supplementary information, xxxx = fault cause.
• For yyyy = 0, the fault cause is decoded bit by bit:
  • Bit 0: Lighting system failed.
  • Bit 1: Signal amplitude too low.
  • Bit 2: Position value incorrect.
  • Bit 3: Encoder power supply overvoltage condition.
  • Bit 4: Encoder power supply undervoltage condition.
  • Bit 5: Encoder power supply overcurrent condition.
  • Bit 6: The battery must be changed.

• p0404 (encoder configuration effective): bit p0404.8 decides how the fault value of this fault is read — with the bit at 1 it decodes as yyyyxxxx hex, at 0 the fault value is for internal Siemens troubleshooting.
• r0949 (fault value): read here, interpreted binary, to obtain the fault cause and supplementary information that Encoder 1 reports.
• p0491 (motor encoder fault response ENCODER): the manual cross-references this parameter for this fault — it sets the drive's response to a motor encoder fault.

The fault is acknowledged with a pulse inhibit (PULSE INHIBIT): inhibit the pulses, acknowledge the fault, and the drive can then be restarted. Where the same condition is configured as an alarm or as a message without reaction, the manual specifies no reaction and no acknowledgement.