Control area network in vehicles

V tem dokumentu so obravnavana kontrolna omrežja v motornih vozilih. Predstavljeno je kontrolno omrežje CAN, ki ga za zmanjšanje kompleksnosti povezav med različnimi sistemi v svoja vozila vgrajuje večina avtomobilskih proizvajalcev. Vgradnja CAN v vozila omogoča preprostejši razvoj sistemov, boljše vzdrževanje in večjo prilagodljivost z dodajanjem in odstranjevanjem posameznih funkcij. Poleg tega zmanjšanje težo in stroške proizvodnje vozila. Protokol CAN je zelo zanesljiv in robusten komunikacijski protokol serijske komunikacije za prenos podatkov visokih hitrosti do 1 Mbit/s. Zagotavlja močno zaščito pred zunanjimi motnjami z uporabo dveh linij CAN H in CAN L po katerih se prenašajo signali nasprotne polaritete. Sprejemniki z merjenjem potencialne razlike tako odstranijo vpliv zunanjih motenj. Poleg tega se za doseganje visoke stopnje integritete prenosa podatkov uporabljajo močni ukrepi odkrivanja napak, kjer lahko enote zavzamejo različna stanja pošiljanja okvirjev napak. Dostopanje enot do skupnega CAN vodila poteka po principu istočasnega dostopa z bitno arbitražo, kjer prevlada sporočilo z najvišjo prioriteto. Prenos informacij je zasnovan na naslovih sporočil in ne na naslovih sprejemnikov. V nalogi so opisane izvedene meritve na CAN vodilu. Prikazani so rezultati merjenja upornosti CAN vodila, merjenja CAN signalov z osciloskopom in merjenja povprečnih napetosti v različnih napetostnih stanjih vozila. V zadnjem delu naloge so opisane izvedene simulacije napak na CAN vodilu. Obravnavani so odzivi sistemov, porajanje signalov na CAN linijah in rezultati diagnostike z diagnostičnim orodjem.This document describes the controller area networks in motor vehicles. It is presented network CAN, which is mostly used by car manufacturers. Installation of control networks in the vehicle drastically reduce the complexity of connections between different systems, it reduces the weight of the vehicle and the cost of the vehicle production. The CAN protocol is very reliable and robust protocol serial communication data transmission of high speed up to 1 Mbit / s. CAN protocol provides strong protection from external interference by the two lines CAN H and CAN L through which is transmitted signals of opposite polarity. Receivers by measuring the potential difference eliminate the influence of external interference. In addition, in order to achieve a high degree of integrity of the data transmission CAN uses strong measures to detect faults. Units may take different states to send error frames. Accessing units to a common CAN bus runs on the principle of simultaneous access with the bit arbitration, which prevails access messages with the highest priority. The transfer of information is based on the message addresses and not the addresses of receivers. The thesis describes measurements carried out on the CAN bus, which shows the results of measuring the resistance of the CAN bus, measurement CAN signals with an oscilloscope and measurement the average voltage in various voltage states of the vehicle. The last part of the thesis describes simulations of errors on the CAN bus. The present system responses, the emergence of signals on the CAN lines and the results of diagnosis using a diagnostic tool