How Modbus Is A Type Of Communication

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Modbus is a type of communication among many devices connected to the same network, for example a system that measures temperature and humidity and communicates the results to a computer. Modbus is often used to connect a supervisory computer with a remote terminal unit (RTU) in supervisory control and data acquisition (SCADA) systems. [17]
In simple words, it can be explained as a method used for transmitting information over the lines between electronic devices. The device asks the information is called the Modbus Master and the devices supply information is Modbus Slaves. In a standard Modbus network, there is one Master and up to 247 Slaves, each with a unique Slave Address from 1 to 247. The Master can also write information to the
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This number tells the slave which table to be accessed. It also decides whether to read from or write to the table.
3.2 Internet Protocol
The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet. Each computer (known as a host) on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet.[18]
While data transferred in a network, is sent or received(for simple understanding, an e-mail note or a Web page), the message is divided into little pieces called packets. Each of these packets includes both the sender 's internet address and also the receiver 's internet address. A packet is firstly sent to a gateway computer which is the first station of the Internet. The gateway computer reads the destination address and forwards the packet to an higher gateway which reads the destination address and transfer it over the internet until one gateway recognizes the packet as belonging to a computer within its area or domain. The packet then is sent by gateway directly to the computer which address is specified.
3.2.1 Subnet
A subnet represents all the devices found at one location. It can be a building or the same local area network (LAN). If a company 's network are divided into subnets that allows everyone to connect to the Internet with a single shared network address. If there is no

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