Motion based profiles, libraries ease integration
When determining the best standards, protocols, and solutions for a motion application, it’s always best when done from the point of reference of the motion profiles. Electrical engineers and programmers must ask what must be accomplished with the motion system and work toward solutions that push the user to the correct methodology.
When implementing a CNC system, for example, engineers wouldn’t want to use CAM tables; they would opt for the longtime standard of G-code. For a packaging machine, on the other hand, system designers would likely use CAM tables and point-to-point motion as G-code, which is quite typical in the worlds of metalworking and woodworking, but would appear to be a strange duck when in the territory of a vertical form/fill/seal machine. Packaging is also home to numerous communication and programming standards, such as PLCopen (IEC 61131-3) and PackML from OMAC. Robotic applications are still another unique area. Control programming software offers electronic gearing, camming, G-code, and robotics kinematics that can serve product tracking, product orientation, pick-and-place, and other motion control applications.
Tools and libraries available match a wide range of motion application types. In this way, engineers can learn and work with one programming environment whether the machine is implementing point-to-point, NC, CNC, and/or robotics, across many industries and machine types for packaging, plastics, alternative energy, and entertainment engineering. With all the possible motion control devices that might be required and application types involved, automation software eases the integration of numerous motion-specific technologies (drives, actuators, motors, etc.) and auxiliary components. Numerous software driver tools facilitate connection to these kinds of industrial components and more, while managing multiple fieldbus networks for seamless integration.
Whether dealing with a simple motion application with a couple axes or a complex system with dozens of axes of motion or more, it is possible today to run the bulk (or all) of the logic on one hardware device if a multi-core-enabled PC-based controller is used. This technology could come in the form of a cabinet-mounted industrial PC (IPC) or a DIN rail-mounted embedded PC. The latter comes with a form factor that is much like a PLC or PAC and provides the convenience of a direct connection to I/O terminal systems.
For the motion network, it’s also best to standardize on a “do it all” solution. Among industrial Ethernet protocols, EtherCAT, for example, can serve as an I/O fieldbus and as a motion bus. Via the EtherCAT Technology Group (ETG), the network is supported by numerous globally active drives vendors, resulting in dozens of commercially available EtherCAT servo drives.
Apply standards-based selection criteria with system openness in mind for all aspects of a motion control system. For every element—from the controller hardware, to the software, to the network—it’s best to bank on solutions that, of course, provide an easy way in, but more importantly an easy way out, permitting the integration of other best-in-class, standards-based solutions.
– Matt Lecheler is motion specialist with Beckhoff Automation. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering, email@example.com.
See an article on platform integration below.