Abstrakt:
In computerized numerical control (CNC) systems,
the communication bus between the controller and axis servo
drives must offer high bandwidth, noise immunity, and time determinism.
More and more CNC systems use real-time Ethernet
protocols such as Ethernet Powerlink (EPL). Many modern controllers
are closed costly hardware-based solutions. In this paper,
the implementation of EPL communication bus in a PC-based
CNC system is presented. The CNC system includes a PC, a
software CNC controller running under Linux Real-Time Application
Interface real-time operating system and servo drives
communicating via EPL. The EPL stack was implemented as a
real-time kernel module. Due to software-only implementation,
this system is a cost-effective solution for a broad range of applications
in machine control. All software systems are based on GNU
General Public License or Berkeley Software Distribution licenses.
Necessary modifications to the EPL stack, Linux configurations,
computer basic input/output system, and motherboard configurations
were presented. Experimental results of EPL communication
cycle jitter on three different PCs were presented. The results
confirm good performance of the presented system.
