Data Acquisition Sensor Network Based on CAN Communication Protocol

CAN komunikacijski protokol postao je standard u automobilskoj industriji, ali njegovu primjenu nalazimo i u nekim drugim područjima zahvaljujući njegovoj robusnosti, odličnim performansama te brojnim drugim značajkama. Cilj ovoga rada bio je pojasniti mogućnosti i značajke CAN komunikacijskog protokola i realizirati pokazni primjer senzorske mreže koja razmjenjuje podatke koristeći taj protokol. Opisane su mogućnosti i razlike između operacijskih sustava za rad u stvarnom vremenu FreeRTOS i Micrium OS. U praktičnom dijelu ovog rada prikazana je uspostava komunikacije između dvije mikrokontrolerske platforme putem CAN sabirnice. Pri tome su korišteni predstavnici Cortex-M i Cortex-R procesorskih profila te je na njima uspostavljen rad CAN sučelja uz pomoć odgovarajućih programskih alata i razvojnih okruženja. Programska potpora na oba sustava ostvarena je korištenjem operacijskog sustava FreeRTOS. Osmišljeni pokazni primjer na zahtjev čita i obrađuje podatke sa senzora temperature, vlage i tlaka BME280 na jednom razvojnom sustavu, a zatim šalje te podatke korištenjem CAN komunikacijskog protokola na drugi razvojni sustav koji primljene podatke ispisuje na terminal osobnog računala.CAN communication protocol has become a standard in the automotive industry, but it also finds its application in other fields, due to its robustness, excellent performance, and many other features. The aim of this paper was to explore the possibilities and features of the CAN communication protocol, and to build a demonstrative example of a sensor network that exchanges data using this protocol. Some main features and distinctions between FreeRTOS and Micrium OS real-time operating systems were studied and described. The communication between two microcontroller platforms via CAN bus is presented as a result of practical work. The software for CAN based communication between development kits, based on Cortex-M and Cortex-R processor profiles, was developed using the appropriate tools and integrated development environments. Software on both systems is based on FreeRTOS operating system. In the designed demonstration example, one development system gathers data from temperature, humidity and pressure sensor BME280 and sends sensor data via CAN bus to another development kit, which then further sends the received data on the personal computer terminal