User guide

Configuring an Application www.controltechniques.com 37
Saturation Breakpoint 1
The rated level of flux in most induction motors causes
saturation. Therefore, the flux against flux producing
current characteristic is non-linear. The effects of
saturation are to cause a step increase in torque when
operating in torque mode as the speed increases into the
field- weakening region. The user can simulate the
non-linear behavior by defining two breakpoints on the flux
vs. magnetizing current curve. This information is often not
provided by the motor manufacturer, but can be measured
by using the Unidrive SP AutoTune feature (See “Run Auto
Tune Button” on page 37). The range for the Saturation
Breakpoint is 0 to 100% of rated flux.
For more information on the Saturation Breakpoint
parameter, please refer to the Unidrive SP Advanced User
Guide.
Saturation Breakpoint 2
See Saturation Breakpoint 1.
Motor Parameters Column
Motor Parameters column is a column of data displayed on
the Motor tab within the Drive/Encoder view (See Figure
54). This column of data contains the values for each of the
motor data parameters. The values in this column are
unavailable if the “Use Motor Data From .ddf File”
checkbox is selected. This means that since the data is
associated with the .ddf file, it cannot be changed. The
values in this column become available when the “Use
Motor Data From .ddf File” checkbox is cleared. The user
can then change one or more of the parameter values
because there no longer linked to data in the .ddf file.
If the user does edit motor parameter values on this tab,
then those values are only stored within that particular
configuration file. In order to save the values to the .ddf file,
the user must click the “Save .ddf Values” button on the
right side of the tab.
The parameters displayed in the Motor Parameters column
will change depending on what is selected (Servo or
Closed-loop Vector) in the Drive mode list box on the Drive/
Encoder view.
Values from Drive Column
The Values from Drive column is a group of parameters
that are constantly being read from the Unidrive SP. The
theory of operation is that the user will often perform an
AutoTune function that reads/measures/calculates data.
The results of those measurements are read from the drive
and displayed in the Values from Drive column. Once they
are displayed in PowerTools Pro (in the Values From Drive
column) the user can apply those values to the Motor
Parameters column by clicking on “Apply to Config.”, in the
middle of the Motor tab (this button looks like a series of
arrows pointing from the Values from Drive column
towards the Motor Parameters column).
The values in the Values from Drive column are not saved
as part of the configuration file. To save these values, the
user must use the "Apply to Config" button to save them.
This column is only functional when online with the
SM-EZMotion module. When offline, the values in the
Values from Drive column will all read zero.
Apply to Config. Button
When the user runs the AutoTune feature available in the
Unidrive SP, PowerTools Pro reads the results of the
AutoTune and displays them in the Values from Drive
column of the Motor tab. After the AutoTune, the measured
values are only saved in the Drive NVM, and not in the
SM-EZMotion module. Therefore, in order to store the
values in the SM-EZMotion module, the AutoTune values
must be applied to the configuration file. When the user
presses “Apply to Config.”, the values in the “Values From
Drive” column are transferred into the Motor Parameters
column. Then the values must be downloaded by
downloading the entire configuration file using Device >
Download.
Run Auto Tune Button
The Unidrive SP has the ability to run an AutoTune
operation thereby measuring several different motor
parameters. Doing so allows the drive to obtain certain
parameters that are not typically provided by the motor
manufacturer, and also optimizes other drive parameters
to work properly with the connected motor/load.
PowerTools Pro allows the user to initiate this AutoTune
feature from the Motor tab on the Drive/Encoder view.
There are several different AutoTune procedures that can
be used depending on the Drive mode selected on the
Drive/Encoder view. These procedures are as follows:
While in Servo mode, there is only a single test that
measures Motor Phase Resistance, Motor Phase
Inductance, and Encoder Phase Angle.
While in Closed-loop Vector mode, there are two different
tests. One test measures the Motor Phase Resistance and
Motor Phase Inductance. The other test measures the
same parameters as the first test in addition to the Motor
Stator Inductance and Saturation Breakpoints 1 and 2.
To initiate an AutoTune from within PowerTools Pro, click
on the Run AutoTune button on the right side of the Motor
tab on the Drive/Encoder view. The user will then get a
pop-up window with warnings and instructions related to
the AutoTune procedure.
Some AutoTunes cause motion while others do not. Some
AutoTunes should be run with the motor unloaded, and
others with the load attached. It is important to read and
understand the warnings and instructions on the AutoTune
windows. An example of one of the AutoTune windows is
shown in Figure 55.