Communication is at the core of the Allen Bradley ControlLogix PLC platform. The following networks are available for a ControlLogix rack.
EtherNet/IP
ControlNet
DeviceNet
DH+
Modbus
You can configure your system for information exchange between a range of devices
and computing platforms and operating systems.
EtherNet/IP Network
Ethernet Industrial Protocol (EtherNet/IP) is an open industrial networking standard that supports both real-time I/O messaging and message exchange. It is a high speed network and as no established schedule. Ethernet tends to be used as a communication link between the PLC and HMI/SCADA systems.
The Ethernet network can also be used to monitor and program PLC’s on the network using the RSLogix programming products.
ControlNet Network.
The ControlNet network is an open, state-of-the-art control network that meets the demands of real-time, high-throughput applications. The ControlNet network uses the proven Common Industrial Protocol (CIP) to combine the functionality of an I/O network and a peer-to-peer network providing high-speed performance for both functions. The ControlNet network gives you deterministic, repeatable transfers of all mission-critical control data in addition to supporting transfers of non-time-critical data.
ControlNet tends to be used for remote I/O applications and PLC to PLC communications. Due to the fact that ControlNet is deterministic a schedule for the network must be created. The schedule is created with the RSNetWorx software package.
A ControlNet network can also be used in a non scheduled way to monitor and program PLC ’s on the network using the RSLogix 5000 programmer.
Each Ethernet device will require an IP address, and each ControlNet device will require a node number between 0 to 99. A schedule also needs to be created for the ControlNet network this is created with the program RSNetWorx for ControlNet. This is explained in the ControlNet section of the manual
DeviceNet Network.
The DeviceNet network is an open low-level network that provides connections between simple industrial devices (such as sensors and actuators) and higher-level devices (such as PLC controllers and computers). The DeviceNet network uses the proven Common Industrial Protocol (CIP) to provide the control, configure, and data collection capabilities for industrial devices. The DeviceNet network is a flexible network that works with devices from multiple vendors.
DeviceNet is commonly used to communicate to plant I/O devices and variable speed drives.
A configuration file is required by the DeviceNet module this is created and downloaded with the RSNetWorx for DeviceNet software package
Watch the video related to modbus
Excel’de Scada Nasil Yapilir? How to make scada using excel? Modbus IO server. Fultek Kontrol Sistemleri www.fultek.com.tr www.fultek.com.tr
Help answer the question about modbus
I want to communicate my PLC with frequency drive through a protocol, but which one should I use?There are lot of protocols available like modbus , profibus , canbus , tcp/ip etc. So exactly how to decide which protocols to use and what are the factors to decide the protocol?
About Author
Author is and Automation training company www.dat.co.uk , who offer a wide range of Automation course for PLC’s (Programmable Logic Controllers), SCADA and HMI systems and variable speed drives.
This is a great project. Will you be so kind to share the project files with me. I want to do some home automation, and this would be ideal.
Thanks for posting your video. It is really good to see pic micro projects.
I am new to pic micro’s and already admire their power.
Thanks
Ivan
Man great work,its relly admirable,I was wondering if i can get this project to have an idea on how to work with citect scada,iam a beginner i hope ill get better like you sumday
,Best of luck for the future,You have a fan of your work.
Slavery is outlawed in most countries. You'd better watch what you say.
Modbus is a popular (and cheap/easy) protocol that all Schneider/Modicon PLCs speak. It is cheap because it is in the public domain and everyone has written drivers using that. Twidosoft and Twidosute (free downloads) botj contain Modbus drivers that can be configured, verified, and run with the Modicon PLCs.
never heard of such a thing
Modbus allows for communication between many devices connected to the same network, Not just computers, but different devices
Take a look at the wiki for exaples and more detailed info
http://en.wikipedia.org/wiki/Modbus
a "Modbus Splitter" allows two or more Modbus Masters to communicate with a network of one or more Modbus Slaves: Thus "Splitting" the network and allowing multiple Masters to communicate with a single network of Modbus Slaves.
Modbus is the protocol developed by Modicon to talk with a
RTU (Remote Terminal Unit)
Your question does not make sense…….
An interface establishes a connection or boundary between the software and hardware. Say, if you want to access information about RAM an interface would provide the programming required to get the information displayed.
Protocol provides a method to acquire the communication. When talking RS232/Rs485 you are identifying converters which manipulate modulation.
For the quality of connectivity over distances you are indeed on the right track. RS232 coupled with Modbus will give you an overall better quality because the transmittion is sent over as plain form (text). Modbus is peer-to-peer but can perform over point-to-point and multidrop networks.
The hardware and wires are the same, Ethernet commonly uses Cat 5E wire and RJ-45 8 conductor connectors. They are the ones that look like an overgrown modular phone plug.
Modbus is a communications protocol, and would not be the same protocol as what your home or office network is using to communicate between computers and printers even though it is Ethernet hardware and wiring.
Modbus would commonly be used between a PLC and other devices such as an engine, turbine or generator controller (Many such devices exist) to gather data and take it back to a central HMI (Human-Machine Interface) or alarm annunciator. Some such devices can be controlled using Modbus as well.