The Advanced Kollmorgen Driver (AKD) Servo Drive is a smart servo drive that has many advanced control features. While the AKD can act as a simple amplifier, its advantage over analog control drives is that it can run its own position and velocity control loops. Using the AKD in Fieldbus mode allows the drive to receive position and velocity commands over EtherCAT from an EtherCAT master.
Starting in SoftMotion 2013 SP1, support has been added to write velocity and torque setpoints to the EtherCAT AKD's internal control loops. These additional features can be accessed through new SoftMotion properties and methods. These properties and methods are available only for EtherCAT AKD and EtherCAT Plugin Axis types and only for SoftMotion 2013 SP1 and later.New Axis Properties
It can be accessed using a SoftMotion Axis Property Node. (Functions pallete >> Vision and Motion >> NI SoftMotion >> Property Node (NI SoftMotion)
). Click on the Property Node and choose Axis Settings >> Axis Control Mode.
This property can be used to change the control mode by which the drive is currently operating. There are four options: Automatic, Position, Velocity, and Torque. Check the Axis Settings: Axis Control Mode Property
help page for more details.
The AKD will display o0 on its digital display when in position mode, o1 when in velocity mode, and o2 when in torque mode as shown in the image below.
New Axis Methods
They can be accessed using a SoftMotion Axis Invoke Node (Functions pallete >> Vision and Motion >> NI SoftMotion >> Invoke Node (NI SoftMotion)
). Click on the Invoke Node and choose Write
. You will see the following methods.Write Position Setpoint:
This method will write a setpoint to the internal position control loop on the EtherCAT drive. Write Velocity Setpoint:
This method will write a setpoint to the internal velocity control loop on the EtherCAT drive.Write Torque Setpoint:
This method will write a setpoint to the internal torque control loop on the EtherCAT drive.Note:
Writing any of these setpoints will erase the previous setpoint from memory on the EtherCAT drive. Note:
These properties and methods also apply to SoftMotion Drive Interface axes for third-party EtherCAT drives that support Profile Torque and Profile Velocity mode. For a full list of supported EtherCAT slaves, check Using EtherCAT Motion Drives with NI Real-Time Controllers