What causes Beckhoff TwinCAT 3 (XAR/XAE) with EtherCAT fault NC 0x4650?

1. Drive in fault state: Read the drive’s own diagnosis (e.g. AX5000 diagnostic messages, EL72xx diag history) and fix that first. 2. Reset sent, drive still starting up: Wait for the drive ready status after reset before enabling. 3. Drive enable or supply missing (including a safety stop): Check power stage supply and enable signals; a TwinSAFE/STO stop must be cleared by the safety sequence, not bypassed.

TwinCAT NC Error 0x4650 (18000) Drive Not Ready

Beckhoff: the drive hardware is not ready for operation, because the drive is in an error state (hardware error), is in its start-up phase (e.g. after an axis reset preceded by a hardware error), or lacks the controller enable. Start-up after a hardware error can take several seconds.

Diagnose this with AI

Upload a keypad photo, the fault history or a parameter export from your Beckhoff TwinCAT 3 (XAR/XAE) with EtherCAT. InduQT compares the evidence and suggests the next useful checks.

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When it happens

When enabling or moving an axis
Right after an axis reset following a drive error
After EtherCAT communication to the drive was interrupted

Likely causes and checks

1Drive in fault state

Points to it: Drive shows its own error code (drive display, diagnosis history or CoE).
Check: Read the drive’s own diagnosis (e.g. AX5000 diagnostic messages, EL72xx diag history) and fix that first.

2Reset sent, drive still starting up

Points to it: Error repeats only if the move is started immediately after MC_Reset.
Check: Wait for the drive ready status after reset before enabling.

3Drive enable or supply missing (including a safety stop)

Points to it: No drive error but no ready; STO or power stage supply off.
Check: Check power stage supply and enable signals; a TwinSAFE/STO stop must be cleared by the safety sequence, not bypassed.

Telling it apart

0x4650 is the drive not ready; 0x4260 is the NC controller enable missing from the PLC.
0x4651 (life counter) and 0x4655 (I/O data invalid / WcState) point to communication rather than the drive.

Evidence to collect

Axis online tab and drive diagnosis
Drive diagnosis history (CoE / drive manager)
EtherCAT State and WcState of the drive
Logger export

Work on fuel trains, burners, pressure vessels and electrical equipment must be done by qualified personnel following the manufacturer’s documentation and local codes. Never bypass a safety device or interlock.

Beckhoff TwinCAT 3 (XAR/XAE) with EtherCAT fault NC 0x4650: Drive hardware not ready to operate (18000)