High speed bus analysis Field bus and real time communication in high levels of EMI
[Examensarbete på avancerad nivå]
In this report, high speed bus communication alternatives in high levels of EMI are investigated. The intended target is a weld system consisting of several parts where one is a power source. Weld power sources are subject to safety regulations regarding electrical safety. Therefore electronic communication between different ground potential regions are subject to high isolation requirements.
Hardware, protocol and software application aspects are evaluated using theoretical investigations and practical evaluations. Communication links with hard and soft real time requirements are investigated, with a focus on low total system cost. Cheap Plastic Optical Fiber links and Fast Ethernet links were evaluated in a lab setup with regards to the electrical, link speed and real time requirements. Software protocol handling was optimized for the embedded target system.
Laboratory evaluations indicated that the use of copper Ethernet was possible with regards to EMI. The use of cheap Plastic Optical Fiber links also provide sucient data rate, while at the same time providing high galvanic isolation and EMI immunity.