IEC−60870−5 application layer for an open and flexible remote unit

This paper presents the development and test of the standard IEC-60870−5 application layer protocol for a Remote Terminal Unit (RTU) based on open hardware and software. The RTU hardware is an embedded system, a SoC-type design using FPGA that has been programmed with the open core LEON with Linux operating system running over it, so both the hardware and IOS are open source. For prototyping the GR-XC3S-1500 board has been used. There is no open source code available for the IEC standard protocols, so application layer protocol has to be implemented. All the software design has been made in a PC platform using standard development tools. The source code generated for the protocol has been compiled with the standard Linux gcc compiler in LEON. Several tests have been made to prove the right behavior of the protocol as well as its performance over different transmission mediums.