Delta Computer Systems TMC 188/40 Series Manual page 31

TMC 188/40 Motion Control Module
Length/transducer count =
The SCALE parameter can also be adjusted or fine tuned by using position readings from the
TMC 188/40 and actual physical measurements in the following formula:
SCALE = Old SCALE x
Where:
OLD SCALE is the default SCALE or a previously calculated SCALE.
Measured position is in position units (thousandth of an inch, etc.) based on a physical
measurement of the system. Position readings are taken using the ACTUAL POSITION
parameter.
NOTE: If you get a negative value for SCALE, use the absolute value and change the DIRECTION
parameter from 0 to -1 (or vice versa).
SCALE Calculation Examples
Example 1
For a system using a magnetostrictive transducer with a calibration number of 9.0110 s per
inch, a position unit of 0.001 inch, and four recirculations, the SCALE will be:
Position Units
TRANSDUCER COUNTS
SCALE = 0.99978 x 32768 = 32761
Example 2
For a system using a magnetostrictive transducer with a calibration number of 9.0110, a
position unit of 0.1 millimeter, and one recirculation, the SCALE will be:
Position Units
TRANSDUCER COUNTS
SCALE = 1.0158 x 32768 = 33285
Fine Tuning for Example 2
Measured Position 1 = 1 meter = 10,000 position units
Position Reading 1 = 10873
Measured Position 2 = 2 meters = 20,000 position units
Position Reading 2 = 20805
SCALE = 33285(Old SCALE) x
Delta Computer Systems, Inc. 360/254-8688
Position Units per inch
Cal Number x 27.75 x Number of Recirculations
Measured Position 1 - Measured Position 2
Position Reading 1 - Position Reading 2
1000(Position Units Per Inch)
=
9.0110 x 27.75 x 4
254(Position Units Per Inch)
=
9.0110 x 27.75 x 1
10000 - 20000
10873 - 20805
Motion Control Parameters
= 0.99978
= 1.0158
-10000
= x 33285 = 33513
-9932
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