General concepts
1.
GENERAL CONC
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Ref.2105
FXM|FKM
SERVOMOTOR
Feedback replacement
The deterioration or poor performance of the feedback device integrated
in a synchronous motor with permanent-magnets forces the user to
replace it.
An encoder may be coupled to the motor shaft in infinite positions one
relative to the other. There is only one correct position and that is why,
once they are coupled, it is necessary to correct the offset generated
when coupling it in an arbitrary relative position unless the correct position
is known in advance.
This process is known as rho adjustment and its purpose is to eliminate
this offset between the zero mark and the result of the one resulting from
the magnetic field generated by the magnets.
RHO adjustment
There is a command that may be executed under the conditions
described later in this manual to obtain the value of the offset between the
reference signal (zero mark) and the position of the vector resulting from
the magnetic field generated by the magnets.
This command is:
The procedure is the following:
Separate the motor from the machine.
Remove the defective feedback device and insert a new identical one
in an arbitrary position.
Once the motor has been separated from the machine and free to turn
(without brake), make sure that the drive that is going to control it is
capable of providing the motor with its rated current.
Without applying power, check that no errors come up at the drive or
at the CNC.
Set the CNC in DRO mode or with high following error to allow the
movement generated by the command itself that will be executed next.
Execute the GC3=3 command.
Apply power so the motor moves searching for the existing offset
generated from having mounted the feedback device arbitrarily when
replacing the defective one.
Monitor the value of GC3 until the command ends without errors.
MANDATORY.
Before replacing the feedback device integrated into the motor or
AXD/ACD drive, make sure to make a safety backup copy of all the
parameters saved in the drive for future updates of the motor.
Note.
When replacing an encoder, it is necessary to adjust the offset,
i.e. the relative position of its reference signal (zero mark) with respect
to the vector resulting from the magnetic field generated by the
permanent magnets of the rotor.
WARNING.
If no backup copy of the parameters was made before the replacement,
the value of parameter RP5 (FeedbackRhoCorrectionParamenter) will be
unknown and, if the rho is not adjusted, it may be dangerous for the user
after replacing the feedback device because the motor may run away. Not
entering the right value in parameter RP5 could generate a dangerous
situation identical to the previous one.
GC3
S34291
Autophasing
Note.
When the execution of GC3 is done, the motor will return to its
origin position.
