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Exchanging data with the sensors and the actuators.

Sensors networks

See also ...


  Automation > Resources > Technologies > Networks > Sensors and actuators  

  Image transfer networks

IO-link, a field communication interface  


AS-I, DeviceNet, Interbus, P-NET, Profibus-DP and Profinet-IO.

Talking With Sensors And Actuators Over A Network

The sensors and actuators networks are low level networks well adapted to the automation of a workshop, of a production line or of a machine.

The main purposes of these networks are to reduce the cost of the connections, to make easier the installation, the adjustments, the operations and the maintenance of the industrial automation devices linked to the network.

Some network interfaces specify the network infrastructure, the hardware protocols and the software protocols all together.

Some other interfaces such as IO-Link specify the standard use to exchange the data.

These protocols can be encapsulated in other protocols using various topologies and media.

AS-I - AS Interface

AS-I consortium.

AS-I, A Low Cost Network Easy To Install

The "AS-I bus" is a low cost sensors and actuators network based on a master / slave architecture and supports the most current topologies.

The time critical data (the inputs and the outputs of the slaves) are transmitted by cyclic polling, when the other types of data (such as configuration parameters) are transmitted asynchronously.

Its first specificity is that it needs only one line (two wires) to transport both the 24 VDC electrical power and the data.

Its second specificity is that you can quickly and easily add a new slave by using "snap and go" modules.

The data are transmitted through hardware methods, firstly by encoding them (Manchester encoding), secondly by modulating the power line with alternate pulse for data transfer (ATM technology).

The "AS-I" sensors and actuators communication system can provide safety features when necessary.

AS-I Technology  

The "AS-Interface" association provides a whole of technical information by e-learning in its virtual academy.

You will find there all the fundamental knowledge to get about the technology : the full description of the AS-I based systems, the presentation of many devices and the presentation of the master-slaves nodes.

You will read a list of many problems which can occur while designing or installing an "AS-I" application, with practical examples illustrating how to implement correctly a network.

The AS-interface association offers a knowledge data base including the most frequently asked questions (FAQ), advices for installation, as well as applications examples.


What is DeviceNet ? , Devicenet overview, Installation guide.

DeviceNet, An Automation Network For Inputs And Outputs

"DeviceNet" is an industrial communication system part of the CIP network system family.

It has been designed to operate communications at the lowest level of an automated plant, in order to exchange data between programmable controllers and field devices.

"DeviceNet" is based on CAN bus concerning the physical layers, and on the CIP protocol concerning the upper layers. Actually, DeviceNet is an adaptation of the CIP protocol to the CAN standard.

The DeviceNet communication system provides some useful additional features such as hot plugging, diagnostic capabilities, redundancy capabilities and more.

The DeviceNet sensors and actuators bus uses the producer-consumer model and the client-server model in order to manage the data flow between the different installed devices.

According to its configuration, DeviceNet can operate either in a master-slave architecture or in a distributed architecture using point to point data exchanges.

DeviceNet Educational Papers  
DeviceNet Installation Guide  

This guide focuses on the "DeviceNet" media and how to design and to install a "DeviceNet" communication system.

You will learn how to set up a DeviceNet network, what are the available topologies and what are the different available media.

Then, you will read a description about the cable system and its components, the connections, how to compute the power requirements, how to diagnose network problems and how to prevent them.


What is Interbus ? , Interbus technology basics, Technical papers.

Interbus As A Fast Industrial Network For Sensors And Actuators

"Interbus" is a sensors and actuators deterministic bus supporting hot insertion, originally designed by the Phoenix contact company.

Nowadays, it is embedded into the Profinet IO network system from the Siemens company.

(Profinet IO is compliant with the previous versions of "Interbus", by using a dedicated proxy as a gateway).

"Interbus-Safety" is a specific version of "Interbus", dedicated to safety networking applications.

"Interbus" uses a ring topology with branches looking like a tree topology, since it uses a single line only through all the devices to send both the requests and the answers.

According to the communication process, "Interbus" uses a single-master / slaves model, and exchanges the data through two channels : one for the process data (the inputs and the outputs) and the other for the services data (configuration, diagnostic and more).

In its late versions, "Interbus" integrates the TCP/IP protocol in a separated channel.

One of the Interbus specificity is that the addresses depend on the physical location of the devices in the network.

A second specificity is its IO data transfer optimization, implemented by using a single frame for all the devices.

To operate configuration, monitoring and diagnostic of Interbus, there is only a single tool (CMD) available for all the control systems.

Interbus Technology And Network Interfaces  

The "Interbus" association provides some documentation about its networking technologies.

Downloadable Interbus informations, drivers and software.

Interbus Technology Overview

IO-link - Communication Interface For Sensors And Actuators

IO-link Technology Overview And Basics  

"IO-link" is a communication interface intended for the lowest field devices such as sensors, actuators or instrumentation devices.

This overview presents the IO-link technology basics, its main features, its architecture, a short resume about the communication mode and the protocol, how to operate it basically, and where to find detailed informations.

Shortly, "IO-link" is not really a network, but rather a protocol operating as a complement to the well known industrial networks.

It is especially designed to communicate with smart sensors and actuators, adding dynamic adjustment capabilities, diagnostic functions and more.

P-NET - The Process Network

What is P-Net ? , P-Net technology basics, Installation guide.

An I/O Network For Process And Manufacture Industries

"P-Net" is a process fieldbus, registered as an international standard under IEC 61158 reference.

The "P-Net" bus has been designed by the "Proces Data" company in Denmark, and it is evolving continuously.

The "P-Net" communication system has been expressively designed to exchange data with sensors, actuators and measurement devices and to provide device configuration as well as device diagnostic services.

The multi-master / slaves model is used to process the communication, using the token communication technique to manage the master accesses (implemented as a virtual token).

P-Net supports multiple topologies (ring, tree, star), segmentation (multi networks technique), hot plugging, redundancy, and it is rather media independent.

One of its specificities is that the address of a device can be changed while the bus is operating.

By the time being, P-Net supports Ethernet TCP/IP, since it embeds the early RS 485 messages in the Ethernet frames, leading in a full factory automation distributed network system.

P-NET Technology Overview  

The International "P-NET User Organization" (IPUO) promotes the "P-Net" standard and provides some technical informations.

P-NET Installation Guide  

"Proces Data", the designer of the "P-Net" digital communication system, presents the P-Net technology and how to use it in this folder.

The first section presents all the currently available topologies to operate a "P-Net" network : ring, bus (trunk or linear), wireless topologies, and how to operate redundancy.

The second section explains the integration of P-Net into IP network systems and how to install such configurations : P-Net over Ethernet IP, over wireless IP networks and over Internet.

The last section carries on wiring considerations.


Tutorial And technical Informations  


Technical Documentation  

The "Profinet-IO" network (a Profinet bus specialized as a network talking with sensors and actuators) seems not yet to be a topical question.

The solution used by the Siemens company to answer this need is the Interbus network, following a strategic deal with the Phoenix Contact company by merging their solutions.

Nevertheless, to satisfy your's curiosity, or whether you need it, you will take advantages by reading the introduction to Profinet IO provided by

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