2.3. Controller area network (CAN) bus
CAN Bus is a robust serial communication which initially created for automotive application (see [4]).
It is designed to allow microcontrollers to communicate each other within a vehicle without a host
computer by implementing a message-based protocol (not an address-based protocol). This mean, the
message is not transmitted from one node to others based on addresses. The mechanism of the CAN Bus
can be described as follow: (1) one node in the networks transmit a message through the network—known
as “Bus”. This message is embedded as a priority and contents of the data being transmitted. (2) All nodes
in the system receive every message transmitted on the Bus. Then, it is up to each node to decide whether
the message received should be discarded or kept. By interfacing microcontroller to computer to utilize
the CAN Bus, the computer as the main controller is also can be considered as a node (as well as other PV
modules). (3) If one node transmitted a message which consisted of a command angles to each PV
modules, then the system utilizing CAN Bus as described in Fig. 3 can be established.
In short, suppose there are n+1 nodes representing n-th PV modules and one node for the main
controller (computer), then the main controller can receive data message from each PV module which
transmitted their parameters. Based on these parameters, computer may calculate the azimuth angle and
zenith angle of the sun in the sky. And so, by using this scenario, many PV modules can be controlled
remotely from a single computer.