Advanced NI SoftMotion Module Axis Interface Reference
ExamplesPublish Date: May 06, 2010
Overview
NI SoftMotion Module 2009 and later provides the software tools
to create a motion controller from almost any LabVIEW RealTime
controller. This document provides some advanced examples for using
the Axis Interface provided with NI SoftMotionPremium Module. Axis
Interface gives access into the SoftMotion engine and lays out the
framework for sending that data to IOmodules other than the
standard NI-951x modules (NI 9512, NI 9514, NI 9516). An example of
this would be a stepper applicationusing the NI 9477 Digital Output
module for step and direction commands. Users interested in
creating standard motionapplications with NI-951x modules should
review the standard examples that ship with NI SoftMotion. The
ability to customize IOand provide non-standard interfaces and
triggering would be the typical cases for using Axis Interface.
1. Introduction
The Axis Interface examples that ship with NI SoftMotion Premium
provide insights in creating 1-2 axis applications. Theseexamples
are helpful and should be reviewed but they do not provide a
scalable architecture for creating higher axis examples.Using the
copy-paste per axis approach, the FPGA quickly runs out of space at
typically 3-4 axes and the RT controller is boggeddown with a
number of redundant loops. The following example provides RT VIs
that scale to any number of axes (provided thatthe RT controller
has enough memory and CPU bandwidth) and multiplexed FPGA code that
scales to 8+ axes.NI SoftMotion Premium with the Axis Interface
provides a way for OEMs and other high-axis count application
developers toreduce cost and provide specialized and custom
functionality. However, small and one-time applications should
strongly considerusing the NI-951x modules. These highly-integrated
modules do not require FPGA programming and pack a variety of IO
thatwould require 3+ standard C-Series IO devices to create the
same functionality. They provide the easiest and most direct
methodfor creating motion control systems from LabVIEW RT devices.
The increase in complexity and software cost in implementing
AxisInterface with NI SoftMotion Premium will typically not
outweigh any potential savings with lower cost IO modules for all
buthigh-axis and OEM applications.Before using these advanced
examples, users should be familiar with the .NI SoftMotion Axis
Interface documentationThe same general architecture in standard
Axis Interface examples exists in these advanced examples. Changes
to sub-VIs havebeen made to create a more scalable and efficient
architecture to handle large axis count systems.Reference Examples
System Requirements:
NI LabVIEW 2009 or laterNI LabVIEW RT 2009 or laterNI LabVIEW
FPGA 2009 or laterNI SoftMotion Module 2009 or laterPremium
Figures 1 & 2 show the Front Panel and Block Diagram of the
RT High-Axis Stepper.VI
Figure 1: Front Panel of Axis Straight Line Example.VI
2/2 www.ni.com
Figure 2: Block Diagram of Axis Straight Line Example.VI
Versions 3.0 of the Reference Examples have RT/FPGA examples
for: Stepper
This code is not supported by National Instruments. Questions
about this example can be posted on NI Discussion Forums: Motion
Control and Motor Drives 2. Reference Links
NI SoftMotion: Create Your Custom Motion Controller on Any
Platform with LabVIEWNI SoftMotion Axis Interface documentationNI
Discussion Forums: Motion Control and Motor Drives
