A DISTRIBUTED CAN BUS BASED EMBEDDED CONTROL SYSTEM FOR

This paper describes a distributed embedded system that uses a high performance mixed signal controller C8051F040 for its DAQ nodes and is based on CAN bus protocol for remote monitoring and controlling of various subsystems of 750 keV DC accelerator based irradiation facility at RRCAT, Indore. A PC with integrated PCI CAN card communicates with intelligent DAQ nodes over CAN bus and each node is interfaced with a subsystem. An opto isolated SN65HVD230 CAN driver is interfaced between each node and physical bus. Remote frames and message prioritising are used for efficient control. The PC application is developed using LabVIEW 8.6. The proposed system is more reliable and noise immune as compared to previously used systems that initially used a centralized system based on C8051 controller. This was then upgraded to a distributed system that used microcontroller AduC812 and communicated over RS485 link. The new system has been integrated and tested satisfactorily for its designed performance with test jigs that simulated the actual subsystems with a bus length of 75 meters. First the complete scheme of the system is presented, and then the hardware and software designs are discussed.