ABB IRB 2000, Product Manual

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5.3.4
COMMOFF, Commutation offset
Description
To obtain the maximum torque when controlling a.c. motors, the angular position of
the rotor in relation to the stator must be known to the control system.
Definition
The commutation offset for an a.c. motor package is defined as the angular position in
resolver increments of the fine resolver when the rotor stands in a certain position in
relation to the stator. The commutation offset is defined in the position when the
rotor has been rotated so that the markings on the fixed stator and the
movable rotor coincide.
Parameters
System parameters for commutation offset are required for all a.c. motors i.e. for
robot axes 1-6 and external axis 7 with internal drive unit for control of the a.c.
motor.
Menu C Selection of axis.
Def. range
0-8191 resolver increments.
If a non-acceptable value is entered an error message is shown.
Default value
1 These parameters are not predefined in the PROM. When loading predefined
parameters from the PROM to the parameter memory, the commutation offset
for all axes 1-6 is set to undefined.
2 The default value for axis 7 is 2048(adjusted for certain factory commutated
motors).
3 The values which apply for the robot installation are always specified in the
robot ID-document.
It is therefore important to define the resolver parameters after loading the
predefined parameters from the PROM.
Menu selection
UPDATE = The actual position of the resolver is transmitted by the control system
to the parameter memory. This assumes a rotor position in accordance
with the definition above.
MANDEF = Manual entry of the commutation offset to the parameter menu.
5.3.5
SYNCOFF, Synchronizing offset
Description
To obtain correct handling of TCP and thereby straight lines, the position of the
resolvers in relation to the mechanical must be known to the control system.
Definition
The synchronization offset for an installed motor package is defined as the
angular position, in resolver increments, of the fine and coarse resolvers, when
the robot axes and external axes are in the synchronization position (calibration
position in systems with absolute measurement). When in this position, the
synchronization offset can be read on the programming unitThe value of the fine
resolver together with a counter (or coarse resolver) gives the possibility to
calculate a absolute position without synchronizing the robot
INSTALLATION S3
5:63