Anilam Wizard 411 - Linear Error Compensation; Non-Linear Error Compensation

28 II
II – 1 Installation Setup
Linear Error Compensation
Linear error compensation can be applied, if the results of the
comparison with a reference standard show a linear deviation over the
whole measuring length. In this case the error can be compensated by
the calculation of a single correction factor. See Fig. II.5 & Fig. II.6.
8 Once determined, the encoder’s error information is entered
directly. Press the TYPE soft key to select LINEAR compensation.
8 Enter the compensation factor in parts per million (ppm) and press
the ENTER key.
Non-Linear Error Compensation
Non-linear error compensation should be applied, if the results of the
comparison with a reference standard show an alternating or
oscillating deviation. The required correction values are calculated and
entered in a table. Wizard 411 supports up to 200 points per axis. The
error value between two entered adjacent correction points is
calculated with linear interpolation.
Starting a Non-linear Error Compensation Table
8 Select Non-linear by pressing the TYPE soft key.
8 To start a new error compensation table, first press the EDIT TABLE
soft key.
8 All correction points (up to 200) are equally spaced from the start
point. Enter the distance between each of the correction points.
Press the Down arrow key.
8 Enter the table’s start point. The start point is measured from the
scale’s reference point. If this distance is not known, you can move
to the location of the start point and press TEACH POSITION. Press
ENTER.
Configuring the Compensation Table
8 Press the EDIT TABLE soft key to view the table entries.
Fig. II.5 Linear error comp., calculation formula
To calculate the linear error compensation use this
formula:
Correction factor LEC =
with S = measured length with reference
standard
M =measured length with device at axis
Example
If the length of the standard you used is 500 mm
and the measured length along the X-axis is
499.95, then the LEC for the X-axis is 100 parts
per million (ppm).
LEC =
LEC = 100 ppm
(rounded to the nearest whole
number)
()
S – M
M
x 10
6
ppm
()
500 – 499.95
499.95
x 10
6
ppm
Fig. II.6 Linear error compensation form
Non-linear error compensation is only available on scales
with reference marks. If non-linear error compensation
has been defined, no error compensation will be applied
until the reference marks have been crossed.