
4. SERVO FUNCTION DETAILS B-65150E/04
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<6> For the vertical axis, adjust the torque offset. (This is unnecessary
for the horizontal axis.)
For the vertical axis, the estimated disturbance value is not
centered at level 0. Torque offset adjustment is done to center the
estimated disturbance value at level 0.
1980
−
Torque offset parameter
2087 1087
In the above example, the influence by gravity is about −1 (A). So, set
the torque offset parameter as follows:
1. When the motor is running at a constant velocity, read the
minimum and maximum estimated disturbance values.
2. Setting the minimum and maximum values as A (A) and B (A)
(both are signed values), respectively, the parameter value can be
obtained from the following expression (for digital).
Torque offset parameter = −(A + B)/(maximum amplifier current
value) × 3641
Let the minimum and maximum values be A(V) and B(V) (both
with a sign), respectively, when measuring an estimated
disturbance with the analog check board. The value to be set in
the parameter is obtained using the following expression:
Torque offset parameter = −(A + B) × 828
Example)
If you read the minimum and maximum values as −1.9 A and
−0.1 A in the above chart (the amplifier used is rated at 40 A
maximum), the torque offset parameter = −[(−1.9) +
(−0.1)]/40 × 3641 = 182. The following chart applies when
the parameter is set with 182.
Estimated disturbance value level 0
Estimated disturbance value center
line
Influence by gravity
Maximum value B
Minimum value A