Appendix C: QSBX/40 Module
TMC 188/40 Motion Control Module
Delta Computer Systems, Inc. 360/254-8688
90
Example 2
1,000 PPR quadrature encoder (4,000 quadrature encoder counts per 1 revolution)
Lead screw ratio = 1 inch of travel per 5 revolutions
Mechanical resolution = 20,000 counts per inch
Total travel = 6 inches
Maximum quadrature encoder counts = 4,000 x 5 x 6 = 120,000
Option 1
SCALE = 20,000
Units of measurement = 0.001 inch
Usable resolution = 1,000 parts per inch
Option 2
SCALE = 2,000
Units of measurement = 0.0001 inch ((SCALE / 1000)/mechanical resolution)
Usable resolution = 10,000 parts per inch
Note: A SCALE of 1,000
cannot
be used because it would mean using a unit of
measurement of 1/20,000 (0.00005 inch) and a total travel of 120,000 units (6 inches x
20,000), which is greater than the maximum ACTUAL POSITION count limit of 65535 units.
OFFSET
(Default: 0; -32,768 minimum, 0 maximum)
The OFFSET parameter determines the range of numbers accepted by the TMC 188/40-(T)Q as
valid REQUESTED POSITION values. OFFSETS are always negative, and the minimum limit of
the range is the OFFSET. The maximum limit is the OFFSET value plus 65,535.
Example:
OFFSET
Position Range
-10,000
-10,000 to 55,535
