Servo Filter Adjustment - JVL MAC050 User Manual

2.10
2.10.1

Servo filter adjustment

The MAC motor contains a higher-order digital filter regulation core. The purpose of the
filter is to ensure that the desired speed, torque and/or position are achieved and sec-
ondly that stability is obtained.
The motor's default setting (when delivered) is normally appropriate for most applica-
tions. The only necessary adjustment is the LOAD parameter which is available via the
Main setup in the MacTalk software. For more demanding applications, the Filter selector
can be used.
2.10.2 Adjusting the LOAD parameter
The LOAD parameter must be increased proportional to the inertia of the payload in the
system. The default value of the LOAD parameter is 1.0000.
The proper LOAD value must be determined as follows.
LOAD=(Motor inertia+Load inertia)/Motor inertia.
If the load inertia is not fully known, it is highly recommended to slowly increase the
LOAD parameter until the motor starts to be unstable and noisy. Then decrease the val-
ue 20-30% to obtain a certain safety margin.
Remember to save the adjustment permanently in the motor by pressing the "Save in
Motor" button.
2.10.3 Exceptions when adjusting LOAD
Precautions must be taken if the transmission from the motor to the load is elastic or in-
volves a certain amount of backlash. A typical situation where precautions must be taken
is when using a belt drive actuator, since the motor's forces may have to be transmitted
past a gear, for example, and then the belt until the payload is finally met. This "transmis-
sion chain" is typically very elastic and the gear will contain a certain amount of backlash.
The main problem is that the motor does not directly "see" the final payload.
When the motor starts to rotate, it will not "sense" the payload before the backlash dis-
tance is passed and the belt is tightened. It is therefore not a linear system and the LOAD
cannot be increased as much as in theory.
JVL A/S - User Manual - Integrated Servo Motors MAC050 - 4500
Servo filter adjustment
Adjust Load according to the attached inertia.
Example:
A system uses a MAC800. The MAC800 has a motor inertia
of 0.92kg/cm² (according to technical data in appendix).
If the load inertia is 9.2kg/cm² (motor intertia x 10) the Load
needs to be adjusted to
LOAD=(Motor inertia+Load inertia)/Motor inertia
LOAD=(0.92 + 9.2) / 0.92 =
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