Overview

Activation

Crosstalk compensation is activated in the axis machine data record of the slave axis by P-AXIS-00789 (lr_param.crosstalk).

Programing Example

Excerpt from the axis parameter list:

lr_param.crosstalk 1

Notice

Crosstalk compensation can also be used for a gantry axis group. A compensation value list must then be specified for each axis in the gantry combination (crosstalk compensation slave).

Compensation value lists can therefore have different settings for each gantry axis.

Activating/deactivating

Crosstalk compensation (ON if compensation is activated) can be switched on or off at any time when the slave axis is at standstill. The slave axis command positions displayed are offset with the offset values.

Filter:

These compensation values can be smoothed by using a sine-square filter. The parameter P-COMP-00064 (n_cycles) switches the filter order to activate it.

Direction dependency of compensation

If position errors are dependent on the motion direction, compensation can be configured direction-dependent using the P-COMP-00084 parameter.

Crosstalk compensation modes

Three modes are provided for crosstalk compensation.

Mode 1:

An acceleration and the related compensation value are specified. With accelerations less than the specified values, the compensation value is linear interpolated.

Mode 2:

Compensation is calculated using an adaptation axis which is obtained by the user conducting three measurement tests. The measurement tests are conducted at various positions on the adaptation axis. Compensation is then calculated using the position of the adaptation axis and the current acceleration.

Mode 3:

Two adaptation axes can be specified. The user can enter up to 15 measurement tests in the compensation value list. Crosstalk compensation calculates compensation values using surface interpolation.

Here, please note that the measurements must cover the complete workspace. If this is not the case, incorrect compensation values can occur with positions outside the specified measuring range.

Management data of the crosstalk compensation list

General data of the list body is entered in the structure kw.crosstalk.*. It contains the following elements.

Management data elements

Variable name	Type	Meaning
mode	UNS08	Compensation mode
master_dyn_ax_nr	UNS16	Logical axis number of the master axis whose acceleration is used as the input variable of the compensation list.
master_pos1_ax_nr	UNS16	Logical axis number of the first adaptation axis.
master_pos2_ax_nr	UNS16	Logical axis number of second adaptation axis
n_cycles	UNS16	Number of cycles of the sine-square filter.
manual_activation	BOOLEAN	0: (Default) The CNC activates crosstalk compensation automatically as soon as the required preconditions are met.
max_points	UNS32	Number of measurement tests in the compensation value list.
acceleration	SGN32	Acceleration [mm/s²] in case of axis excursion.
deceleration	SGN32	Negative acceleration [mm/s²] in case of axis excursion.
velocity_dependent	BOOLEAN	Different compensation values for different motion directions.

Compensation values of crosstalk compensation

The corresponding compensation value of the slave axis is entered for each acceleration in the list kw.crosstalk.table[i].*. The compensation list is valid for positive and negative directions of acceleration.

Compensation value list

Variable name	Type	Meaning
position[i].ax_1	SGN64	Position of the first adaptation axis with acceleration test i
position[i].ax_2	SGN64	Position of the second adaptation axis with acceleration test i
position[i].correction_accelerate_dir_pos	SGN64	Compensation value for acceleration in positive motion direction
position[i].correction_decelerate_dir_pos	SGN64	Compensation value for deceleration in positive motion direction
position[i].correction_accelerate_dir_neg	SGN64	Compensation value for acceleration in negative motion direction
position[i].correction_decelerate_dir_neg	SGN64	Compensation value for deceleration in negative motion direction