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Installation manual
CNC 8055
CNC 8055i
7.
CONCEPTS
SOFT: V02.2X
Axes and coordinate systems
It is recommended to begin the process with low jerk values (lower than 10 m/sec3) and low Kv.
They can always be increased in a later readjustment.
Steps for the adjustment
1. Move both axes independently.
The first step is to ensure the perfect operation of both the master and the slave axes separately.
Also verify that both axes move in the same direction with similar dynamics.
To do this, the following methods may be used:
Define a master axis and a slave axis using a separate parameter table for each axis. When
adjusting the master axis, set the slave axis as a dro axis and viceversa.
Cancel the "drive enable" of the slave axis and move the master axis. Change the parameter
settings of the CNC to turn the slave axis into the master axis and repeat the process.
2. Move one of the motors at a constant low speed. Do not make jerky movements because the
second motor is being dragged by the first one. In this situation, any acceleration or deceleration
forces it to go from one side of the backlash to the other thus making it jerky.
Verify that the turning direction of both motors are coherent once the movement has been carried
out.
Verify that the gear ratio in both motors is the same (same feed for same turning speed).
Carry out a basic adjustment of the velocity loop so the machine can move. It will be readjusted
later with both motors together.
Do not set the friction parameters (there is already enough torque to move the machine).
3. Repeat the process with the second motor.
When adjusting the loops, use the same parameters if the motors are identical and the torque
distribution is 50%. If the motors are different, the axes must be adjusted so their dynamic
response is the same or very similar.
When using AC-Forward ("ACFGAIN" = YES), remember that each motor has half the inertia
for a torque distribution of 50%.
4. Enable the tandem with both motors.
Disable the tandem PI, supply power and verify that the system is resting. Enter a low
proportional value and eliminate the integral value of the PI of the tandem.
Then, without pre-load, verify that the machine moves and that each motor provides its
corresponding torque according to parameter "TORQDIST" (e.g. for a 50% distribution, half the
torque).
5. Enable the pre-load.
Monitor the torque of each motor (Sercos variable TV2). While stopped, increase the preload
gradually until the motors supply torque in opposite directions.
Move slowly in both directions and verify that it works properly. Make sure that it is not jerky and
that each motor supplies its corresponding torque according to parameters "TORQDIST" and
"PRELOAD".
Observe that reversing the turning direction of a motor reverses the direction of the torque and,
consequently, it will be necessary to change the direction of its values monitored with drive parameters
SP43 and TP85.
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