The code snippet below shows a simplified initialization procedure. However, as part of an application's initialization procedure, you can read the AKD's position object and reset the NI SoftMotion Axis position to that value. At application start up, the SoftMotion engine initializes the absolute position value for all axes to zero.

The screenshot below shows the location of this variable in a LabVIEW project containing an EtherCAT AKD.īecause the drive uses the absolute position for its internal control loops, you must ensure that the NI SoftMotion axis position is updated with this position. The EtherCAT master converts the object into a shared variable called Inputs-Position Actual Internal Value. Once the feedback is configured, the AKD reports this position feedback using an EtherCAT object that can be read by your LabVIEW application. The AKD will need to be properly configured to use the feedback source using Kollmorgen WorkBench. Using Absolute Encoders with the Kollmorgen EtherCAT AKD Servo Drive To use an absolute encoder instead, replace the I/O and logic in this loop with the I/O and logic used to decode the absolute encoder signal into the same position and velocity feedback signals. The logic in this loop is used to decode an incremental quadrature encoder signal into both position and velocity feedback. This project, as well as other NI SoftMotion sample projects, can be accessed by creating a new project from the LabVIEW splash screen when the NI SoftMotion module is installed and activated*. The screenshot below shows the encoder loop from the top-level FPGA VI in the NI 9502 Brushless Servo Position Setpoint sample project. Using hardware such as the NI 950x C Series Drive Modules which allow for direct connection to a compatible motor, the FPGA bitfile can be customized to accept absolute encoder feedback by changing the feedback loop, which is a quadrature encoder decoder in the examples. NI SoftMotion UDV axes allow the implementation of control loops, feedback, and I/O to be customized on the FPGA.

Using Absolute Encoders with a SoftMotion User Defined Variable (UDV) Axis While NI SoftMotion's examples and the NI 951x C Series Drive Interface Modules only natively support incremental quadrature encoders, there are two methods of using an absolute encoder with your NI SoftMotion application.

Labview softmotion pid control