Networks. In this lesson we will discuss: What do Networks do?

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Blaise Sullivan
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1 Networks In this lesson we will discuss: What do Networks do? Why do industrial installations use them? What networks are available and who owns them? Details of each, hardware (media) and setup software Properties (speed, nodes, redundancy etc.) The most popular network, could it replace the others?

2 Networks What do Networks do? What does the EtherNet network do for you?

3 Networks What does EtherNet do for you? Allows you to: Fetch information from the web Send s Remote control the heating etc. This is just sending and receiving data and, even if you are wireless, there is EtherNet in the system somewhere.

4 Networks Sending and receiving data is what industrial networks do too, it s just the meaning of the data they send that differs. Different data that could be sent: 1) Position demand and feedback 2) Speed demand and feedback 3) Parameter settings (maximum speed for example) 4) Input data in & Output data out.

5 Networks & the need for different types 1) Position demand and feedback This requires a fast and timed Network. independent.co.uk If, for example, we only updated the position demand every twenty minutes we would have problems controlling where it went and wouldn t know where it was.

6 Networks & the need for different types Some position control needs only a periodic update of the speed or position it should achieve Like telling a lathe to go to a position and stay there. Some need better, faster updates. Like this one

7 Networks & the need for different types 2) Speed demand and feedback. Aerial Atom 0-60 in about 2.4 seconds In that time a Servo Motor can go from rpm and stop again 20 times. This needs fast speed demand and feedback signals - another fast timed network required.

Networks & the need for different types 3) Parameter settings (trip current for example) We need to send parameters to and receive them from network

8 Networks & the need for different types 3) Parameter settings (trip current for example) We need to send parameters to and receive them from network connected devices. This is an overload and it has 150 parameters A slow but clever network will do here Overload temperature varies slowly so time has less relevance.

9 Networks & the need for different types 4) Input data in & Output data out. Main PLC Start Stop Fwd Rev etc. Hundreds of Control Cables Each hundreds of Metres long

10 4) Input data in & Output data out. Main PLC The speed and time requirements of the I/O determine whether it needs to be a slow or fast network. Network Cable Start Stop Fwd Rev etc. Local PLC I/O

11 What Networks Common Industrial Networks There are lots of different networks in Industry Some are original and some are just function copies of other networks to allow manufacturers to specify their own network equipment, and make more money So what networks are there?

12 What Networks Common Industrial Networks AS-i Actuator-sensor interface, managed by AS-International, a low level 2-wire bus for basic digital and analogue devices. CANBus - Robert Bosch for use in Cars. Basis of DeviceNet ControlNet Fast with Position control DeviceNet Slow but can store devices parameters EtherNet/IP Mega Fast with many options for the future Interbus, Phoenix Contact's protocol for communication over serial links.

13 What Networks Common Industrial Networks MACRO Fieldbus - Motion and Control Ring Optical developed by Delta Tau. MECHATROLINK Yaskawa. Modbus - Schneider Electric Profibus PROFIBUS International. Honeywell SDS Honeywell. SERCOS - VDW (German Machine Tool Builders' Association)

14 What Networks EtherNet IP EtherNet/IP uses standard Ethernet hardware. Searingly fast, it is built on the TCP/IP protocols, but the "IP" in EtherNet/IP stands for "Industrial Protocol" EtherNet/IP is a network used in non time critical automation networks as you do not know exactly when the information will get through the network. EtherNet is: Extremely fast, cheap and easy to use but non-deterministic.

15 What Networks EtherNet IP EtherNet/IP uses standard Ethernet hardware. Devices need to be specified in the program configuration.

16 What Networks EtherNet IP EtherNet gives us access to the devices information and settings and we can then use the information to make something happen

Needs a Node T for every device on the network.

17 What Networks ControlNet ControlNet is a fast and very clever network providing high-speed transmission of time-critical I/O data and messaging data. Uses Coaxial cable and BNC plugs. Needs a Node T for every device on the network. Very fast, Clever, relatively expensive & Totally deterministic. Easy Network redundancy, use two sets of cables etc and if one network fails then the other will continue. Node T Network Terminator

18 Network update Interval How scheduled bandwidth is used on a ControlNet network: Network Update Interval Non-time Critical Data interchange uses available time Nodes 1 to Smax transmit data every update interval Node to node information interchange

19 Configure Networks ControlNet ControlNet is a scheduled network and requires RS Networx for ControlNet software to setup the update rate and produce the network schedule ControlNet continually updates all of the information to and from the devices on the network every NUT or Network Update Time. ControlNet is: Expensive Reliable (redundant hardware) Deterministic Used in critical processes where failure is not an option

DeviceNet DeviceNet is an unscheduled network

Robust Able to store device parameters for

20 DeviceNet DeviceNet is an unscheduled network Devices on the Network are set to report their status at regular and individual intervals DeviceNet is: Cheap and Cheerful Robust Able to store device parameters for fast device replacement Fast enough for non time-critical use

Configure Networks DeviceNet Network Mapping: This maps the device inputs and outputs to memory locations in the ControlLogix PLC The PLC moves values into and out

21 Configure Networks DeviceNet Network Mapping: This maps the device inputs and outputs to memory locations in the ControlLogix PLC The PLC moves values into and out of the devices to set parameters like how fast the motor should go and read values like temperature or the state of a remote input for example. This system can use COS.

22 Configure Networks DeviceNet DeviceNet uses a program called Networx for DeviceNet Network is not scheduled it is Mapped, it is quite slow, but fast enough to service up to 62 devices as they only talk when necessary.

Configure Networks DeviceNet DeviceNet is clever it can also store the devices parameters so they can be reloaded automatically if a new device

23 Configure Networks DeviceNet DeviceNet is clever it can also store the devices parameters so they can be reloaded automatically if a new device is fitted. This is good for maintenance men As they don t need to get a PC out And remember a ton of parameter values if they fit a new device.

24 Configure Networks DeviceNet This auto setting of parameters saves you setting up to 400 parameter values when you change a Motor drive for example.

25 What Networks Sercos Sercos communicates via optic fibre. The data rates are up to 16Mbit/s and cyclic update rates as low as 62.5µS Sercos also supports a "Service Channel" which allows asynchronous comms with slaves for less time-critical data. Collision-free comms due to a time-slot mechanism. Can control 70 axes of motion at an update of 250 µs Sercos is: Fast, noise immune, used for motion control. Many manufacturers have Sercos capability options in their PLCs

PROFIBUS PA (Process Automation) is used to monitor measuring equipment via a process control system in process automation applications.

26 What Networks ProfiBus PROFIBUS DP (Decentralized Peripherals) is used to operate sensors and actuators and is a Deterministic network. Uses two core screened cable that is violet and its speed varies from 9.6Kbps to 12Mbps. PROFIBUS PA (Process Automation) is used to monitor measuring equipment via a process control system in process automation applications. This network is Non-deterministic. Very Fast and Simple Integration to Siemens PLCs. Accepted in Europe, but expensive, No Power over the Bus. Many manufacturers build in Profibus configuration software.

27 EtherNet IP the Only Network? EtherNet IP could not yet replace ControlNet as it is inherently non-deterministic. EtherNet uses the CSMA/CD bus access scheme (Carrier Sense Multiple Access, with Collision Detect) All Quiet? Send Crash wait All Quiet? Send Crash wait All Quiet? Send.. Receive.. All Quiet? etc.

28 EtherNet IP the Only Network? EtherNet IP could replace DeviceNet as DeviceNet is not deterministic either. A lot of the capabilities in DeviceNet are included in EtherNet/IP and as EtherNet costs reduce it will become increasingly feasible to produce device-level EtherNet/IP products.

29 EtherNet IP the Only Network? EtherNet IP could not replace Sercos as Sercos is deterministic. However Sercos III has been re-engineered into the EtherNet system to allow use of the Sercos real time position monitoring and synchronisation over the Ethernet Network in parallel with standard EtherNet traffic.

30 EtherNet IP the Only Network? EtherNet IP could not replace ProfiBus DP as it is inherently non-deterministic. However the non-deterministic ProfiBus PA could be replaced, though it has a huge installed base and replacement is unlikely in the near future.

31 Networks into the future For the foreseeable future then these networks will remain in use. DP

32 Configure Networks EtherNet IP Manufacturer specific software is available for configuration and programming: Rockwell Logix Software Opto 22 Delta Computer Systems Setting up an EtherNet/IP Connection Emerson Process Management EtherNet IP Module The End

33 Messaging information on DeviceNet with CLX Sending parameter values to the Device (like the max speed parameter) directly by using a message instruction. Configuration button

34 Explicit Messaging on DeviceNet with CLX What do you want to do? Type of Message Source of the value you want to send

Configure Networks ControlNet ControlNet is a scheduled network and requires RS Networx for ControlNet software to setup the update rate and

35 Configure Networks ControlNet ControlNet is a scheduled network and requires RS Networx for ControlNet software to setup the update rate and produce the network schedule ControlNet continually updates all of the information to and from the devices on the network every NUT or Network Update Time.

Printed in U.S.A., Copyright Penton Media, Inc. All rights reserved. Machine Design (ISSN ) is published semimonthly by Penton Media,

Printed in U.S.A., Copyright Penton Media, Inc. All rights reserved. Machine Design (ISSN ) is published semimonthly by Penton Media, Printed in U.S.A., Copyright 2000. Penton Media, Inc. All rights reserved. Machine Design (ISSN 0024-9114) is published semimonthly by Penton Media, Inc., 1100 Superior Ave., Cleveland, OH 44114-2543.