Delta Tau GEO BRICK LV User Manual
Turbo PMAC User Manual
164
Motor Compensation Tables and Constants
Selecting Turbo PMAC Motors to Use
Any two Turbo PMAC motors can be used for the inner and outer loops. If no integration is required in
passing the information from outer loop to inner loop (see below), using a lower-numbered motor for the
outer loop will avoid adding a servo-cycle delay. This has the possibility of delivering higher
performance in closing the outer loop.
passing the information from outer loop to inner loop (see below), using a lower-numbered motor for the
outer loop will avoid adding a servo-cycle delay. This has the possibility of delivering higher
performance in closing the outer loop.
However, in many applications, the performance of the outer loop will be high enough even with the
added delay, and some users will find it easier to add the additional outer-loop motor as a higher-
numbered motor than the real motors. For example, Motors 1, 2, and 3 are the real X, Y, and Z axes,
respectively; Motor 4 is added as the W axis to close a loop around motor 3 as the Z axis.
added delay, and some users will find it easier to add the additional outer-loop motor as a higher-
numbered motor than the real motors. For example, Motors 1, 2, and 3 are the real X, Y, and Z axes,
respectively; Motor 4 is added as the W axis to close a loop around motor 3 as the Z axis.
Inner Loop General Setup
In hybrid control applications, first set up the inner loop as a standard positioning motor, get it well tuned
and operating as needed when controlling this actuator in position/velocity mode. For the hybrid control,
we will simply add a command from the outer loop through the master position input; otherwise,
operation of this inner loop remains the same.
and operating as needed when controlling this actuator in position/velocity mode. For the hybrid control,
we will simply add a command from the outer loop through the master position input; otherwise,
operation of this inner loop remains the same.
Outer Loop General Setup
Set up the outer loop to use the alternate sensor as its feedback with its Ixx03 and Ixx04 feedback address
parameters (through the conversion table). Often, the control quantity of this loop will not be a position
value, but since all Turbo PMAC terminology is in terms of position, you should beware of possible
confusion. One least-significant bit (LSB) of the feedback sensor is considered a count by Turbo PMAC.
As with positioning motors, the scale factor of the axis-definition statement can permit you to program
this motor in engineering units (e.g. Newtons or pounds of force).
parameters (through the conversion table). Often, the control quantity of this loop will not be a position
value, but since all Turbo PMAC terminology is in terms of position, you should beware of possible
confusion. One least-significant bit (LSB) of the feedback sensor is considered a count by Turbo PMAC.
As with positioning motors, the scale factor of the axis-definition statement can permit you to program
this motor in engineering units (e.g. Newtons or pounds of force).
You will not be able to tune the outer loop until you have linked it with the inner loop. The next section
describes the steps in linking the loops.
describes the steps in linking the loops.
Cascaded Loops for Hybrid Control
Servo
Filter
Amp
M
Output
Device
Device
Servo
Filter
Σ∆t
Ixx02
Ixx05
+
Ixx05
Ixx06
or
ECT
Entry
ECT
Source
Address
ECT
Entry
Ixx02
Motor
E
S
Position
Sensor
Auxiliary
Sensor
-
Commanded
Position
Trajectory
Actual
Position
Virtual PMAC Motor
PMAC Motor for Physical Device
Position Loop
Ixx03,
Ixx04
Auxiliary
Loop
+
-
Commanded
Auxiliary
Trajectory
Actual
Auxiliary
Value
Ixx02
or
ECT
Source
Address
+
Ixx03,
Ixx04
Open
Register