F31805 — Encoder 1: EEPROM checksum error

F31805 is the drive's report that the checksum over the data stored in the EEPROM of Sensor Module Encoder 1 no longer matches: the parameter data held on the module is corrupted. The drive writes the exact cause as a hexadecimal fault value into r0949, so the message value %1 distinguishes an EEPROM access error (01) from too many blocks in the EEPROM (02). Depending on the drive's configuration, the same condition can also be signalled as an alarm (A) or as a message without a reaction (N); this page describes the fault variant.

• The data in the EEPROM of Sensor Module Encoder 1 is corrupted — the internally stored parameter data no longer matches its checksum. The manuals for the different families word this identically in substance, once as corrupted data in the EEPROM, once as corrupted internal parameter data.
• Which of the two underlying problems occurred is shown by the fault value: an EEPROM access error (01) or too many blocks in the EEPROM (02).

1. Read the fault value in r0949, interpreting it hexadecimal: 01 means an EEPROM access error, 02 means too many blocks in the EEPROM.
2. Replace the module, Sensor Module Encoder 1 — this is the only remedy the manuals give for this fault; no repair, re-download or reparameterization step is described.

• The message value %1 carries the fault value, which the drive stores in r0949 and which is to be interpreted hexadecimal:
• 01: EEPROM access error.
• 02: Too many blocks in the EEPROM.

• r0949 — fault value: read it hexadecimal to tell which EEPROM problem the drive detected here, an access error (01) or too many blocks in the EEPROM (02).
• p0491 — motor encoder fault response ENCODER: the manuals cross-reference this parameter for this fault because it sets how the drive responds to a motor encoder fault.

The fault must be acknowledged immediately. In practice this happens after Sensor Module Encoder 1 has been replaced, since replacing the module is the only remedy listed; once the message is acknowledged, the drive can be restarted. If the condition is configured to come as an alarm (A) or with no reaction (N), the manuals specify neither a reaction nor an acknowledgement for those variants.