LAM Technologies DS10 Series, User Manual

Page: 38 / 72

Functionality and Setting DS10xx
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5.2.2 Resolution
The DS10xx drivers permit to choose among many divisions, both of
decimal and binary type, as shown in the following table.
Decimal Binary
Step / Rev Microstep /
Step
Step / Rev Microstep /
Step
1000 5 200 1
2000 10 400 2
4000 20 800 4
5000 25 1600 8
10000 50 3200 16
25000 125 6400 32
12800 64
25600 128
The step/rev in the table are for a stepper motor with 1.8° step angle. If
using a motor with a different step angle, the step/rev number will be
different too. For example, if using a motor with a 0.9° step angle, the
step/rev indicated in the above table must be multiplied by 2.
The resolution selection must be made mostly in accordance with the
application requirements considering that a greater resolution offers also a
better positioning precision and minor vibrations at low speed but, on the
other side, it requires a greater pulses frequency applied to the STEP input.
Instead, low resolutions permit to obtain high motor rotation speeds, even
with modest pulses frequencies applied to the STEP input, but they can
generate vibrations and resonance phenomena when the motor works at low
speeds. Furthermore, the positioning precision is reduced.
In order to correctly evaluate the precision, it must be considered that,
despite the current regulation offered by the driver is accurate, it exist a
mechanical error due to the tolerances and to the constructive features of
the motor. In real applications it is difficult to command motor shaft
variations inferior to 0.05°.
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