# Overview

## Task

When a spindle drive is operated at current limit, it may result in an excessive position lag at high speeds, causing error messages in the drive and/or the CNC. To avoid this, it is necessary at high speeds to change to controlled operation (no position control) and to only operate the spindles position-controlled for positioning movements.

## Properties

Automatic changeover by the CNC with position control in the drive is only available for SERCOS and CANopen drives.

A change between the two operation modes can take place automatically during the movement.

## Release Note

This function is available for CANopen drives as of CNC Build v3.1.3079.13.

## Parameter definition

Automatic changeover and switch-back can be specified by using the appropriate parameters. They are:

- P-AXIS-00264: antr.sercos.op_mode_for_velocity_control
- P-AXIS-00267: antr.sai_op_mode_change.v_velocity_control_on
- P-AXIS-00268: antr.sai_op_mode_change.v_position_control_on

The section Parameters contains a detailed description of the commands.