Thursday, October 4, 2018

Network Basics

What is a Network?


A network provides a means of connecting multiple devices together for the purposes of exchanging information.

→A common example of a network is an office where the computers are connected together with the use of an Ethernet network for the purpose of sending emails or printing documents on a networked printer.



Why use a network in automation?

There are many reasons to use a network. some examples are:
→Data acquisition from the control system.
→The control device in a remote location
→Data sharing between PLC controllers.
→The ability to program devices from a remote location.
→The ability to troubleshoot problems from a remote location.
→The ability to integrate all production areas of a plant.
→To integrate manufacturing systems with business systems.

Why are there so many networks?

There are many different networks exist for a variety of reasons:
→Different manufacturers
Designed for many devices transferring large data blocks
→Designed to inexpensive
→Designed for maximum reliability
Designed to support many communication protocols  

Examples of networks used in industrial automation today:
→Ethernet/IP
→ControlNet
→DeviceNet
→DH+
→Remote I/O
→Foundation Fieldbus
→Profibus DP
→Modbus
→AS-i

Network types

Fieldbus
    A generic term covering all industrial networks
    Note that there is also a specific network known as foundation Fieldbus that is often referred to as just Fieldbus.

Information network
    Typical devices are computers
    In an industrial environment typically PLCs are on the network with computers.
    Common uses are data collection data monitoring, file transfers, and email.

 Control network
     Typical devices are PLCs, HMI terminals, and I/O chassis. 
    A common use is for control of plant floor devices such as I/O chassis, robots, and other intelligent devices.

 Device network
     Typical devices are field devices such as buttons, lights, valves, and drives. Also small blocks of I/O.
     A common use is for direct connection to field devices. 

Sensors
    Typical devices are very simple field devices such as sensors, and lights.
    A common use is for direct connection to field devices.


Common Networks Devices

→Repeater
→Hub
→Switch
→Gateway



Thank you




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