Compensation value lists

Storing of compensation values

The data for the compensation processes

Cross compensation,
Plane compensation and
Leadscrew error compensation

are stored in so called compensation lists for each axis. This lists are interpreted during start up of the control or they can be updated at a later point of time.

	It is possible, to activate for one axis all compensation processes (cross, plane, leadscrew error and temperature compensation) at the same time.

Provision of the compensation table

The following entries must be present in the startup description to announce the compensation table to the control system:

Variable name	Type	Significance
zahl_kw	UNS16	Number of compensation value lists
achs_kw[i]	String	Name of the data file
achs_kw_log_ax_nr[i]	UNS16	Logical axis number of the axis to which the compensation value list is to apply

with i as list index.

CAUTION
If the compensation value list is configured by the TwinCAT System Manager, these entries are made automatically in the startup list.

Example

Excerpt from startup list hochlauf.lis:

Excerpt from startup list

hochlauf.lis: 
: 
zahl_kw               3 
# 
achs_kw_log_ax_nr[0]  1
achs_kw[0]            tc_...\achskw1.lis 
# 
achs_kw_log_ax_nr[1]  2 
achs_kw[1]            tc_...\achskw2.lis 
# 
achs_kw_log_ax_nr[2]  6 
achs_kw[2]            tc_...\achskw6.lis 
:

Structure of the compensation table

The compensation value list consists of a list header in which general data is entered and the list body in which the compensation algorithm is programmed, and which contains the actual compensation table.

List header

The list header is identified in the list by the variable name kopf. It contains the following elements:

Variable name	Type	Significance
kopf.achs_nr	UNS16	Logical axis number of the compensation value list
kopf.log_achs_name	String	Axis name of the axis; is used only for diagnostic purposes.

CAUTION
If the compensation value list is configured by the TwinCAT System Manager, these entries are made automatically in the compensation list.

List body

The list body contains general data and the compensation table. The entries of the list body are identified by structure variable kw.*. For the specific compensation processes it contains the following sub structures:

Variable name	Significance
kw.crosscomp	Data structure for cross compensation
kw.crosscomp2	Data structure for plane compensation (2-dimensional cross compensation)
kw.ssfk	Data structure for leadscrew error compensation

Updating the compensation table

The compensation table can be updated with the control system in operation. The updated compensation table takes effect immediately provided the conditions for action are met.

CAUTION
With reference to the axes positions the NC channel must be synchronized after start-up respectively actualization or reinitialization of a compensation. The subsequent instruction of a fast program start or an axis exchange without requesting axes positions ("FAST") is not allowed.