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HEIDENHAIN ND 1300 VED and Crosshair Systems User Manual

Page 266

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QC-300 Series User’s Guide

SLEC (Segmented linear error correction)

SLEC compensates for encoder non-linearities by applying correction values to individual nonlinear seg-

ments. These SLEC correction values are created by the QC-300 system using data provided by the user

in the SLEC Setup screen. The SLEC setup data provided by the user consists of Standard (certified) and

Observed (measured) values of a standard, or standards that cover the entire range of axis motion.

The SLEC measurements can divide the axis range of motion into up to 150 segments. The example

diagrammed on the next page shows standard values compared to observed values for 6 segments. The

deviation (difference between standard and observed) is also shown. Segments are defined as any straight

line on the graph of deviations, beginning with segment zero.

The standard and observed values at the end of each segment are entered as data for a station in the SLEC

Setup screen. For example, the standard and observed values at the end of segment 0 on the diagram are 40

and 40, and are entered into the Standard and Observed data fields for station 1.

When the procedure is complete and setup data are entered, correction values will be calculated for the

encoder based on the standard and observed values at the end of the segments. The procedure for configur-

ing the SLEC error correction is diagrammed and explained below.

1 Cycle the power to establish a repeatable machine zero. You will be prompted to move the encoders

to cross reference marks or perform a hard stop to the establish machine zero. Perform the machine zero

operation.

NOTE

If a hard stop zero is performed, the same stop will be required each time the QC-300

is started.

2 The length of the calibration standard should cover as much of the range of axis motion as possible.

Move the stage to position the encoder of the axis being calibrated at the beginning (part zero position) of

the calibration standard. Make a note of this calibration axis value shown in the DRO; this will be entered

later as the machine zero (MZ) Offset.

3 Access the setup menu, touch the

SLEC menu item and then touch the Axis

choice field repeatedly to cycle to the axis

that will be calibrated.