# Disabling drive controller in case of bus error (P-AXIS-00542)

P-AXIS-00542 | Disabling drive controller in case of field bus error
Description | By default, the CNC-internal error reaction is executed when a bus error occurs (see also P-ERR-70021) on CANopen drives in order to bring the axis to a standstill. The control bits to the drive controller are not changed. By setting this parameter to the value "ON", enable bits are also reset in the control word for CANopen drives in case of a bus error. In this case, drive-internal functionalities are activated and this leads to the fastest possible stop of the axis with subsequent torque cut-off:

Drive type: Modifications in control word:

CANopen: Resetting bits 0, 3 and 4 (0x0019) in control word (Drive Shutdown)

Parameter | antr.bus_error_drive_disable
Data type | STRING
Data range | DEFAULT: Activation of function depends on drive type: Drive type: Modifications in control word: CANopen* OFF *The default value of OFF for CANopen drives is based on the fact, that it is possible here to switch the drive immediately torque-free by setting object 0x605B (Shutdown option code) to 0 in response to the shutdown command. Otherwise the drive would then not braked when a bus error occurs, which is not desired.

ON: When a bus error occurs, the control word is changed according to the above table.

OFF: If a bus error occurs, the control word is not changed.

Axis types | T, R, S
Dimension | T: ---- | R,S: ----
Default value | DEFAULT
Drive types | CANopen
Remarks | Before using this parameter, it is essential to check in the manufacturer documentation, especially for CANopen drives, whether the above modification of the control word leads to ramp-down of the drive and a subsequent shutdown of the torque.

It makes sense for this parameter to select the same setting as for P-AXIS-00537 which defines the reaction to a position lag error.