PLC Network

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Mạng PLC (PLC Network)

TS. Trương Đình Nhơn Bộ môn Tự động Điều khiển

Email: [email protected]

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Content

§  Basic industrial network §  Profibus

§  DeviceNet §  ControlNet §  ASi

§  Ethernet

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References

[1] Hoàng Minh Sơn - Mạng truyền thông công nghiệp – Nhà xuất bản khoa học và kỹ thuật, 2007

[2] Các tài liệu kỹ thuật thiết bị điều khiển công nghiệp của SIEMENS,

ROCKWELL

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Criteria

•  Midterm 1 (paper test) : 30% •  Midterm 2 (representation) : 30%

•  Final (project) in group : 40%

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Basic Industrial Network

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Historical Overview

In the early 20th century, the process control systems and the manufacturing systems were designed based primarily on the mechanical technology and with analogue devices. After the period, the pneumatic control technology and the hydraulic power were introduced. The pneumatic control technology made it possible to control remote systems by a centralized control system. These technologies are still very common.

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Historical Overview

At the beginning of 1960, a digital computer was for the first time really applied as a digital controller. The term direct digital control (DDC) was used to emphasize that the computer directly controls the process. In the 1960s, the application of a minicomputer was still a fairly expensive solution for many control problems. In the meantime, programmable logic controller (PLC) was developed and it replaced the conventional, relay-based controller, having relatively limited control functions.

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Historical Overview

The numerically controlled (NC) machine tool became to be controlled by computers and the robot was developed in this period. In mid 70s, the first distributed computer control system (DCCS) was announced by Honeywell as a hierarchical control system with a large number of microprocessors. The concept of the DCCS spread widely in many industrial automation systems such as power plant control systems, manufacturing systems, etc.

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Historical Overview

The installation of distributed control systems (DCS) in the newly planned plants or replacement of existing analogue or centralized control systems is presently a common decision of enterprise management. The use of local area networks to interconnect computers and automation devices within an industrial automation system has become popular since 1980. The industrial automation systems are often implemented as an open distributed architecture with communication over digital communication networks.

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Historical Overview

Considerable international standardization efforts have been made in the area of local area networks. The Open Systems Interconnection (OSI) standards permit any pair of automation devices to communicate reliably regardless of the manufacturer.

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Historical Overview

What is an Industrial Network? By definition, an industrial network requires geographical distribution of the physical measurement I/O and sensors or functional distribution of applications. Most industrial networks transfer bits of information serially. With fewer wires, we can send information over greater distances. Because industrial networks work with several devices on the same line, it is easier to add a new device to existing systems.

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Historical Overview

To make all this work, our network must define a set of rules (a communication protocol) to determine how information flows on the network of devices, controllers, PCs, and so on. With improved communication protocols, it is now possible to reduce the time needed for the transfer, ensure better data protection, and guarantee time synchronization, and real-time deterministic response in some applications. Industrial networks also ensure that the system sends information reliably without errors and securely between nodes on the network.

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Historical Overview

For the lower level communication network for industrial automation, the industrial local area network solutions such as MAP are too expensive and/or do not reach the required short response times, depending on the application. The fieldbuses have been developed to meet these requirements, and many efforts are now being made to make fieldbus standards for industrial automation applications.

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Hierarchical Levels in Industrial Networks

The industrial automation systems can be very complex, and it is usually structured into several hierarchical levels. Each of the hierarchical level has an appropriate communication level, which places different requirements on the communication network Figure 1.1 shows an example of the hierarchy of an industrial automation system.

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Industrial networks may be classified in several different categories based on functionality: •  field-level networks (sensor, actuator or device buses) •  control-level networks (control buses) •  information-level networks

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Field level The lowest level of the automation hierarchy is the field level, which includes the field devices such as actuators and sensors. The elementary field devices are sometimes classified as the element sublevel. The task of the devices in the field level is to transfer data between the manufactured product and the technical process.

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Field level The data may be both binary and analogue. Measured values may be available for a short period of time or over a long period of time.

For the field level communication, parallel, multiwire cables, and serial interfaces such as the 20mA current loop has been widely used from the past.

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Field level The serial communication standards such as RS-232C, RS-422, and RS-485 are most commonly used protocols together with the parallel communication standard IEEE488. Those point-to-point communication methods have evolved to the bus communication network to cope with the cabling cost and to achieve a high quality communication.

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Field level Field-level industrial networks are a large category, distinguished by characteristics such as message size and response time. In general, these networks connect smart devices that work cooperatively in a distributed, time-critical network. They offer higher-level diagnostic and configuration capabilities generally at the cost of more intelligence, processing power, and price.

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Field level At their most sophisticated, fieldbus networks work with truly distributed control among intelligent devices like FOUNDATION Fieldbus. Common networks included in the devicebus and fieldbus classes include CANOpen, DeviceNet, FOUNDATION Fieldbus, Interbus-S, LonWorks, Profibus-DP, and SDS.

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Control Level At the control level, the information flow mainly consists of the loading of programs, parameters and data. In processes with short machine idle times and readjustments, this is done during the production process. In small controllers it may be necessary to load subroutines during one manufacturing cycle. This determines the timing requirements. It can be divided into two: cell and area sublevels.

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Control Level Cell sublevel For the cell level operations, machine synchronizations and event handlings may require short response times on the bus. These real-time requirements are not compatible with time-excessive transfers of application programs, thus making an adaptable message segmentation necessary.

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Control Level Cell sublevel In order to achieve the communication requirements in this level, local area networks have been used as the communication network. After the introduction of the CIM concept and the DCCS concept, many companies developed their proprietary networks for the cell level of an automation system.

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Control Level Cell sublevel The Ethernet together with TCP/IP (transmission control protocol/internet protocol) was accepted as a de facto standard for this level, though it cannot provide a true real-time communication. “A de facto standard is a custom, convention, product, or system that has achieved a dominant position by public acceptance or market forces (such as early entrance to the market). De facto is a Latin phrase that means "concerning fact." De facto means "existing in fact,” or "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established.”

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Control Level Cell sublevel Many efforts have been made for the standardization of the communication network for the cell level. The IEEE standard networks based on the OSI layered architecture were developed and the Mini-MAP network was developed in 1980s to realize a standard communication between various devices from different vendors. Some fieldbuses can also be used for this level.

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Control Level Area sublevel The area level consists of cells combined into groups. Cells are designed with an application-oriented functionality. By the area level controllers or process operators, the controlling and intervening functions are made such as the setting of production targets, machine startup and shutdown, and emergency activities.

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Control Level Area sublevel We typically use control-level networks for peer-to-peer networks between controllers such as PLCs, distributed control system (DCS), and computer systems used for human-machine interface (HMI), historical archiving, and supervisory control.

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Control Level Area sublevel We use control buses to coordinate and synchronize control between production units and manufacturing cells. Typically, ControlNet and PROFIBUS-FMS are used as the industrial networks for controller buses. In addition, we can frequently use Ethernet with TCP/IP as a controller bus to connect upper-level control devices and computers.

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Information level The information level is the top level of a plant or an industrial automation system. The plant level controller gathers the management information from the area levels, and manages the whole automation system. At the information level there exist large scale networks, thus we can use Ethernet networks as a gateway to connect other industrial networks.

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Transmission Methods The data communication can be analogue or digital. Analogue data takes continuously changing values. In digital communication, the data can take only binary 1 or 0 values. The transmission itself can be asynchronous or synchronous, depending on the way data is sent. The synchronous mode transmission is more efficient method.

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Transmission Methods The data is transmitted in blocks of characters, and the exact departure and arrival time of each bit is predictable because the sender/receiver clocks are synchronized. The transmission methods in industrial communication networks include baseband, broadband, and carrierband.

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Transmission Methods In a baseband transmission, a transmission consists of a set of signals that is applied to the transmission medium without being translated in frequency. Broadband transmission uses a range of frequencies that can be divided into a number of channels. Carrier transmission uses only one frequency to transmit and receive information.

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Transmission Methods The most common transmission media for industrial communication network is copper wire, either in the form of coaxial or twisted-pair cable. Fiber optics and wireless technologies are also being used.

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Transmission Methods Coaxial cable is used for high-speed data transmission over distances of several kilometers.

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Transmission Methods The coaxial cable is widely available, relatively inexpensive, and can be installed and maintained easily. For these reasons it is widely used in many industrial communication networks.

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Transmission Methods Twisted-pair cable may be used to transmit baseband data at several Mbit/s over distances of 1 km or more but as the speed is increased the maximum length of the cable is reduced.

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Transmission Methods Twisted-pair cable has been used for many years and is also widely used in industrial communication networks. It is less expensive than coaxial cable, but it does not provide high transmission capacity or good protection from electromagnetic interference.

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Transmission Methods Fiber optic cable provides increased transmission capacity over giga bits, and it is free from electromagnetic interference.

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Transmission Methods However, the associated equipment required is more expensive, and it is more difficult to tap for multidrop connections.

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Transmission Methods In many mobile or temporary measurement situations, wireless is a good solution and is being used widely.

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Today's environment Conventional point-to-point wiring using discrete devices and analog instrumentation dominate today's computer-based measurement and automation systems. Twisted-pair wiring and 4-20 mA analog instrumentation standards work with devices from most suppliers and provide interoperability between other 4-20 mA devices. However, this is extremely limited because it provides only one piece of information from the manufacturing process.

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Today's environment Integrating devices from several vendors is made difficult by the need for custom software and hardware interfaces. Propr ie tary networks offer l imi ted mul t i -vendor interoperability and openness between devices. With standard industrial networks we decide which devices we want to use.

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Industrial Network Components In larger industrial and factory networks, a single cable is not enough to connect all the network nodes together. We must define network topologies and design networks to provide isolation and meet performance requirements. In many cases, because applications must communicate across dissimilar networks, we need additional network equipment.

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Industrial Network Components The following are various types of network components and topologies:

Repeaters Router Bridge Gateway

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Industrial Network Components • Repeaters: a repeater, or amplifier, is a device that enhances electrical signals so they can travel greater distances between nodes. With this device, we can connect a larger number of nodes to the network. In addition, we can adapt different physical media to each other, such as coaxial cable to an optical fiber.

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Industrial Network Components • Router: a router switches the communication packets between different network segments, defining the path.

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Industrial Network Components • Bridge: with a bridge, the connection between two different network sections can have different electrical characteristics and protocols. A bridge can join two dissimilar networks and applications can distribute information across them.

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Industrial Network Components • Gateway: a gateway, similar to a bridge, provides interoperability between buses of different types and protocols, and applications can communicate through the gateway.

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The OSI model

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1. OSI - layered framework for the design of network systems that allows communication across all types of computer systems.

2. The OSI 7 Layers. (Brief

functional overview) 3. Vert ical and horizontal

communication between the layers using interfaces. (defines what information and services should the layer provide to the layer above it)

The OSI model

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•  was developed to structure telecommunication protocols in the ’70 (Pouzin & Zimmermann)

•  standardized by CCITT and ISO as ISO / IEC 7498

•  all communication protocols (TCP/IP, Appletalk or DNA) can be mapped to the OSI model.

The Open System Interconnection (OSI) model is a standard way to structure communication software that is applicable to any network.

The OSI model

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•  is a model, not a standard protocol, but a suite of protocols with the same name has been standardized by UIT / ISO / IEC for open systems data interconnection (but with little success)

•  mapping of OSI to industrial communication requires some additions

The OSI model

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Physical

Link

Network

Transport

Session

Presentation 6

5

4

3

2

1

Application 7

"Transport" protocols

"Application" protocols

Definition and conversion of the data formats (e.g. ASN 1)

All services directly called by the end user (Mail, File Transfer,...) e.g. Telnet, SMTP

Management of connections (e.g. ISO 8326)

End-to-end flow control and error recovery (e.g. TP4, TCP)

Routing, possibly segmenting (e.g. IP, X25)

Error detection, Flow control and error recovery, medium access (e.g. HDLC)

Coding, Modulation, Electrical and mechanical coupling (e.g. RS485)

The OSI model

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7. Application Layer

Ø  Provides user interfaces and support for services

Ø  Resource sharing and device redirection

Ø  Remote file access Ø  Remote printer access Ø  Inter-process communication Ø  Network management Ø  Directory services Ø  Electronic messaging (such

as mail) Ø  Network virtual terminals

The OSI model

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6. Presentation Layer

Ø  Translation (connects different computer systems)

Ø  Compression (transmission efficiency)

Ø  Encryption (SSL security)

The OSI model

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5. Session Layer

Ø  Session establishment, maintenance and termination (Deciding who sends, and when.)

Ø  Session support (security, name recognition, logging )

The OSI model

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4. Transport Layer

Ø  Connectionless and connection-oriented services

Ø  Process-Level Addressing Ø  Multiplexing and

Demultiplexing Ø  Segmentation, Packaging and

Reassembly Ø  Connection Establishment,

Management and Termination

Ø  Acknowledgments and Retransmissions

Ø  Flow Control

The OSI model

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3. Network Layer

Ø  Logical Addressing Ø  Routing (where the packet is

destinated to) Ø  Datagram Encapsulation Ø  Fragmentation and

Reassembly (handling too big packets )

Ø  Error Handling and Diagnostics ( using status messages for example )

The OSI model

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2. Data Link Layer 2.1. Logical Link Control (LLC )

Ø  Establishment and control of logical links between local devices on a network.

2.2. Media Access Control (MAC) Ø  The procedures used by

devices to control access to the network medium.

•  Frame sequencing •  Frame acknowledgment •  Addressing •  Frame delimiting •  Frame error checking •  PDU: frame

The OSI model

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1. Physical Layer

•  Definition of Hardware Specifications (of cables, connectors, wireless radio transceivers, network interface cards )

•  Encoding and Signaling (bit representation)

•  Data Transmission and Reception (half duplex, full duplex )

•  Topology and Physical Network Design (mesh, ring, bus)

•  PDU: bit

The OSI model

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Basic requirements: • work in the real-time (time to transmit data from one node to another is determined); • “immunity” to disturbances typical in industrial environment.

Industrial Networks

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Two types of data transmission: • Query-Response; • Broadcast. Uniform data frame format and standard set of functions.

Master-Slave protocols

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This protocol is dedicated for communication between many nodes (peer-to-peer) and guarantees reliability at high speed. The main features: • distributed architecture (there is no central node); • it can be easy extended; • frame dimension is limited; • time is guaranteed, • network can work even if one of the nodes is broken down.

Token-passing protocols

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Two types of frames: • service frames (token); • data frames. Token is transferred between nodes and only the owner of the token can send the frame, that is available for all others nodes. Data are transmitted with a constant sweep depending on transfer speed, the number of nodes and the number of transferred bytes.


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To transfer the token correctly, one should set in each station: • number in the network (unique), • number of the last station. It can be declared in a software or hardware way. Examples of Token-passing networks: Genius of GE Fanuc, Sycoway N10 of CEGELEC.


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Network Topology Industrial systems usually consist of two or more devices. As industrial systems get larger, we must consider the topology of the network. The most common network topologies are the bus, star, or a hybrid network that combines both. Three principal topologies are employed for industrial communication networks: star, bus, and ring.

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Network Topology

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Network Topology A star configuration contains a central controller, to which all nodes are directly connected. This allows easy connection for small networks, but additional controllers must be added once a maximum number of nodes are reached.

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Network Topology The failure of a node in a star configuration does not affect other nodes. The star topology has a central hub and one or more network segment connections that radiate from the central hub.

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Network Topology With the star topology, we can easily add further nodes without interrupting the network. Another benefit is that failure of one device does not impair communications between any other devices in the network; however, failure of the central hub causes the entire network to fail.

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Network Topology In the bus topology, each node is directly attached to a common communication channel. Messages transmitted on the bus are received by every node. If a node fails, the rest of the network continues in operation as long as the failed node does not affect the media.

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Network Topology In the ring topology, the cable forms a loop and the nodes are attached at intervals around the loop. Messages are transmitted around the ring passing the nodes attached to it. If a single node fails, the entire network could stop unless a recove ry mechan ism i s no t implemented.

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Network Topology For most networks used for industrial applications, we can use hybrid combinations of both the bus and star topologies to create larger networks consisting of hundreds, even thousands of devices. We can configure many popular industrial networks such as Ethernet, FOUNDATION Fieldbus, DeviceNet, Profibus, and CAN using hybrid bus and star topologies depending on application requirements.

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Network Topology Hybrid networks offer advantages and disadvantages of both the bus and star topologies. We can configure them so failure of one device does not put the other devices out of service. We can also add to the network without impacting other nodes in the network.

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Benefits of industry-standard networks Modern control and business systems require open, digital communications. Industrial networks replace conventional point-to-point RS-232, RS-485, and 4-20 mA wiring between existing measurement devices and automation systems with an all-digital, 2-way communication network. Industrial networking technology offers several major improvements over existing systems.

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Benefits of industry-standard networks With industry-standard networks, we can select the right instrument and system for the job regardless of the control system manufacturer.

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Benefits of industry-standard networks Other benefits include: • Reduced wiring: resulting in lower overall installation and maintenance costs • Intelligent devices: leading to higher performance and increased functionality such as advanced diagnostics • Distributed control: with intelligent devices providing the flexibility to apply control either centrally or distributed for improved performance and reliability

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Benefits of industry-standard networks Other benefits include: • Simplified wiring of a new installation, resulting in fewer, simpler drawings and overall reduced control system engineering costs • Lower installation costs for wiring, marshalling, and junction boxes

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Benefits of industry-standard networks Other benefits include: Standard industrial networks offer the capability to meet the expanding needs of manufacturing operations of all sizes. As our measurement and automation system needs grow, industrial networks provide an industry-standard, open infrastructure to add new capabilities to meet increasing manufacturing and production needs.

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Benefits of industry-standard networks Other benefits include: For relatively low initial investments, we can install small computer-based measurement and automation systems that are compatible with large-scale and long-term plant control and business systems.

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Common Industrial Networks

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Profibus

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Profibus

The world’s most installed open field-level network • Origin: German Government in cooperation with automation manufacturers, 1989. • Implemented on ASIC chips produced by multiple vendors. Based on RS485 and the European EN50170 Electrical specification. • Formats: Profibus DP (Master/Slave), Profibus FMS (Multimaster/Peer to Peer), and Profibus PA (intrinsically safe).

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Profibus

• Connectors: 9-Pin D-Shell connector (impedance terminated) or 12mm IP67 quick-disconnect. • Maximum Number of Nodes: 127 • Distance: 100M to 24 KM (with repeaters and fiber optic transmission). Baudrate: 9600 to 12M Bit/sec • Message size: up to 244 bytes of data per node per message • Messaging formats: Polling (DP/PA) and Peer-to-Peer (FMS)

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Profibus

• Supporting Trade Organization: Profibus Trade Organization Profibus is commonly found in Process Control and large assembly, and material handling machines. Single-cable wiring of multi-input sensor blocks, pneumatic valves, complex intelligent devices, smaller sub-networks (such as AS-I), and operator interfaces.

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Profibus

Advantages: Profibus is the most widely accepted international networking standard. Nearly universal in Europe and also very popular in North America, South America, and parts of Africa and Asia. Profibus can handle large amounts of data at high speed and serve the needs of large installations. The DP, FMS and PA versions collectively address the majority of automation applications.

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Profibus

Disadvantages: High overhead to message ratio for small amounts of data; no power on the bus; slightly higher cost than some other buses; European- and Siemens- centricity is occasionally an obstacle for some North American users. Profibus’ substantial speed, distance and data handling capabilities make it ideal for many process control and data intensive applications.

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Profibus

Disadvantages: Profibus DP, which is the most commonly messaging format for I/O, is a polling network, meaning that its assigned master periodically requests the status of each node. This ensures that each device on the network (which can send up to 244 bytes of data per scan) is updated consistently and reliably. Each message contains 12 bytes of overhead for a maximum message length of 256 bytes.

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Profibus

Multi-Master: Multiple masters are possible with Profibus DP, in which case each slave device is assigned to one master. This means that multiple masters can read inputs from the device but only one master can write outputs to that device.

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Profibus

Peer to Peer: Profibus FMS is a peer to peer messaging format, which allows masters to communicate with one another. All can be masters if desired. FMS messages consume more overhead than DP messages.."COMBI mode" is when FMS and DP are used simultaneously in the same network.

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Profibus

Peer to Peer: This is most commonly used in situations where a PLC is being used in conjunction with a PC, and the primary master communicates with the secondary master via FMS. DP messages are sent via the same network to I/O devices.

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Profibus

Profibus DP V1 extension: The older FMS specification is giving way to a new approach, DP with V1 extensions. This serves the needs of new devices with greater complexity. The Profibus Trade Organization has released a new specification which integrates many of the functions of Profibus FMS (multimaster, peer to peer communication) together with Profibus DP (master/slave I/O communication) so that the two types of messaging work together to combine synchronous scanning with on-the-fly configuration of devices.

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Profibus

Profibus DP V1 extension: In the past, FMS and DP have been used together, but often for entirely different purposes. This integration enables Profibus to more effectively compete with some of the more advanced capabilities of its rivals, DeviceNet and Foundation Fieldbus.

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Profibus

Profibus DP V2 for motion control: A recent addition to the Profibus specification is V2, which adds 1)  a synchronization feature which allows multiple devices

and axes of motion to work on the same time clock

2)  publisher / subscriber messaging which allows devices to communicate to each other on a one-to-one or one to many basis.

This allows the coordination of synchronized axes of motion.

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Profibus

Intrinsically safe: The Profibus PA protocol is the same as the latest Profibus DP with V1 diagnostic extensions, except that voltage and current levels are reduced to meet the requirements of intrinsic safety (Class I div. II) for the process industry.

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Profibus

Intrinsically safe: Most master cards support Profibus PA, but barriers which convert between DP and PA are necessary (available from a number of companies). PA devices are powered by the network at intrinsically safe voltage and current levels.

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Setup Guide - Profibus communication AC141x with Step 7 V5.5

English

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Seite 109 © ifm electronic

gmbh

Contents:

1.  Connect the Profibus Unit 2.  Create a Project and set the PG/PC Interface 3.  Configure the Hardware 4.  Configure the Profibus Gateway 5.  Transfer the Project 6.  Monitor the Inputs and Outputs

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1.  Connect the Profibus Unit

Siemens PLC with Profibus Interface

ifm AS-i / PB Gateway AC141x Laptop / PC

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2. Create a Project and set the PG/PC Interface

n  Create project Ø Start Simatic Manager

with icon from desktop

Ø Use an appropriate name for the project

Ø Confirm with OK

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2. Create a Project and set the PG/PC Interface

n  Set the PG/PC interface Ø Set the PG/PC-Interface using

„Options -> Set PG/PC Interface“.

Ø Choose the PC from the list of Ethernet interfaces.

Ø Confirm with OK Ø Confirm with OK

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3. Configure the Hardware

n  Add the Simatic Station Ø Add the PLC to the project : „Insert -> Station -> Simatic 300

Station or Simatic 400 Station“

Ø Open the Hardware configuration

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n  Add Rail Ø Add the Rack Rail by using „drag and drop“ on the respective

icon from the catalogue.

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n  Add CPU Ø Add the CPU by using „drag and drop“ to the respective slot

from the catalogue.

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n  Set the Ethernet interface Ø Enter the IP address for the

Ethernet interface of the PLC

Ø Click „New…“ to add the ethernet connection

Ø Enter an appropriate name for the Ethernet connection

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n  Set Ethernet interface Ø The Ethernet interface

„Ethernet1“ is now added. Close the configuration session with OK.

Ø This interface will be used to upload and download the PLC configuration and program

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4. Configure the Profibus Gateway

n  Install GSD File Ø The „Generic Station

Description “ File (GSD File) is required in order to integrate the Profibus gateway into the hardware configuration. When using the Profibus gateway with the Step 7 system for the first time, the GSD File is to be installed via „Options -> Install GSD File….“

Ø Choose the GSD File with „Browse…“

Ø Start the installation

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n  Add the Profibus path – right click on the MPI/DP interface to create the Profibus connection

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n  Add the Profibus path – right click on the MPI/DP interface to create the Profibus connection

1

2

3

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n  Add the Profibus gateway Ø Choose the Profibus gateway from the catalogue using the

following steps: „Profibus DP -> Additional Field Devices -> Gateway -> ifm electronic gmbh -> AS-Interface -> AC1411/12-PB V2.0 and add it to Profibus network.

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n  Description of the Slots Ø Slots 1 - 4: digital IO signals M1/M2 (address 0-63) Ø Slots 5 - 6: analogue inputs M1/M2 (address 256 – 263) Ø Slots 7 - 8: analogue outputs M1/M2 (address 256 – 263)

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n  Description of Slots Ø  Slots 1 - 4: digital IO signals

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n  Description of Slots Ø Slots 5 - 6: analogue inputs/outputs, Ø Data mapping and corresponding parameter setting:

–  analogue channels per input / output slave" = 1 –  analogue channels per input / output slave" = 2 –  „analogue channels per input / output slave" = 4 is not suitable for this

representations since it can be defined by the user. .è Complete table for data mapping is given in the Device Manual

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5. Transfer the Project

Ø Save the configuration using Ctrl + S or „Station -> Save and Compile“

Ø Load the configuration to PLC using Ctrl + L or „PLC -> Download“

Ø If the configuration is correct, the bus error LEDs (BF 1 and BF 2) are out and the system error LED (SF) of the CPU is green.

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6. Monitor the Inputs and Outputs

Ø Create a Variable Table (VAT) in Step7 Ø Insert -> Range of Variables…

Ø IW for Input Words or PIW for Periphery Input Words Ø IB für Input Bytes or PIB for Periphery Input Bytes Ø Ix.y for Input-Bits, for example . I64.1 for bit 1 in input byte 64 Ø -> Read inputs via monitor variable (glasses)

Ø QW for Output Word or PQW for Periphery Output Word Ø QB for Output Byte or PQB for Periphery Output Byte Ø Qx.y for Output Bit, for example Q64.1 for bit 1 in output byte 64 Ø -> Outputs can be set via Variable Control

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Ø Add variable table by right clicking left window, Insert New Object –> Variable table

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Ø Open VAT table by clicking on VAT1 Ø To add variables, Go to Insert à Range of Variable

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Ø To Monitor values, Variable à Monitor

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DeviceNet

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DeviceNet

DeviceNet - fieldbus for low and mid-level factory networking • Origin: Allen-Bradley, USA, 1994 • Based on CAN (Controller Area Network) technology, borrowed from the automotive industry • Maximum Number of Nodes: 64 • Connectors: Popular ‘Mini’ 18mm and ‘Micro’ 12mm waterproof quick disconnect plugs and receptacles, and 5 pin phoenix terminal block.

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DeviceNet

• Distance: 100M to 500M • Baudrate: 125, 250 and 500 Kbits/sec • Maximum Message size: 8 bytes of data per node per message • Messaging formats: Polling, Strobing, Change-of-State, Cyclic; Explicit messaging for configuration and parameter data; UCMM for peer to peer messaging. Producer/Consumer based model.

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DeviceNet

DeviceNet Network Example

Cable to open-style connector on

network PLC scanner

KwikLink cable

Termination resistor

RightSight photo sensor

Insulation displacement

connector CompactBlock I/O module

ArmorBlock maximum

4 I/O points

Power supply


Open-style connection for power supply

Prox switch and cable Stack light

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DeviceNet

Sample of Some DeviceNet Media Components

Thick round drop line cable

KwikLink drop line cable

KwikLink flat trunk line cable insulation

displacement connector

Device port

T-port

KwikLink flat trunk line cable

DeviceLink

137

DeviceNet Purpose

n Open network n Link low-level devices to PLCs

Ø Sensors Ø Pushbutton stations Ø Distributed I/O blocks Ø Intelligent motor started overloads Ø Variable frequency drives

138

DeviceNet Open Network

n Open network n Network devices (nodes) can be purchased from many different

vendors n Network managed by Open DeviceNet Vendors Association

(ODVA) Ø ODVA.ORG

139

DeviceNet Advantage

n Save wiring costs Ø Rather than run power wires separately to each device Ø  Rather than run signal wires from each field device separately back to PLC, I/O module connect devices directly to a network Ø One cable with four wires

–  Two power wires –  Two signal wires

140

Field Devices More Intelligent

n Traditional systems Ø A photo switch counting pieces as they pass on a conveyer

was wired directly into an input module. n Counter programmed on ladder to track parts’ count n Counter done bit triggered output point to control field action

141

DeviceNet Advantage

n Many DeviceNet devices are intelligent. n Photo switch has counters and timers

incorporated into sensor. n PLC does not need to have timer or counter

on ladder. n When timer or counter is done, the action is

carried out through RSNetWorx for DeviceNet software to trigger field device across the network.

142

DeviceNet Components

n PLC with DeviceNet scanner n RSNetWorx software for DeviceNet n Trunk line n Drop lines n Nodes n Minimum one power supply n Two 121-ohm ¼-watt termination resistors n Up to 64 nodes

143

DeviceNet Network Example

Cable to open-style connector on

network PLC scanner

KwikLink cable


RightSight photo sensor

Insulation displacement

connector CompactBlock I/O module

ArmorBlock maximum

4 I/O points

Power supply


Open-style connection for power supply

Prox switch and cable Stack light

144

Sample of Some DeviceNet Media Components

Thick round drop line cable

KwikLink drop line cable

KwikLink flat trunk line cable insulation

displacement connector

Device port

T-port

KwikLink flat trunk line cable

DeviceLink

145

DeviceNet Cabling

n Thick round n Thin round n KwikLink cable n Special-use cable n Open-style connectors

146

Thick Round Cable

n Used for trunk line n T-ports used to connect from trunk line to drop lines

147

Thin Round Cable

n Typically used for drop lines n Can be used for trunk in short networks with low current

requirements

148

KwikLink DeviceNet Connection

KwikLink flat cable

Insulation displacement connector

149

Insulation Displacement Connection

n For non-wash down n Typical usage conveyor lines n Mount on inside rail of

conveyor n No conduit needed n Easy installation of new nodes n No minimum spacing

150

DevicePort

n Passive 4- or 8-point taps n Connected to trunk line by drop line n Previous slide showed an 8-point DevicePort n Nodes connected to DevicePort by drop lines

151

T-port

n Used to connect drop line to trunk line n Drop line connected to DevicePort and then on to multiple nodes n Drop line connected directly to node n Maximum drop line length 20 feet

152

DeviceLink

n Adapter to interface non-DeviceNet devices to network n 2- or 3-wire 24-V sensors n Mechanical limit switches n Any non-DeviceNet device with relay contacts n One required for each non-DeviceNet node

153

Additional Media

n Refer to the DeviceNet Media catalog for a complete listing of available products.

154

Maximum Trunk Line Length (1 of 2)

n Maximum cable distance between any two nodes n Not necessarily actual length of backbone n Maximum length determined by cable type and baud rate

155


156

Trunk Line Calculation One

Node number

157

Example One

n Left terminating resistor to node 1 is 12 feet. n Drop line node 1 is 2 feet. n Right terminating resistor to node 12 is also 12 feet. n Node 12 drop line is 2 feet. n From node 1 drop line to node 12 drop line is 800 feet.

158

Trunk Line Calculation (1 of 2)

n For this example, trunk line length is maximum length of cable between terminating resistors.

159

Trunk Line Calculation (2 of 2)

n 12 + 800 + 12 = 824 feet n Refer to table for maximum baud rate of network.

160

Maximum Trunk Line Length

Trunk line length is over 820 feet so maximum baud rate for this network is 125 K.

161

Trunk Line Calculation Two

Power Supply

1

2

3

4

5

6

7 8

9

10

11

12

13

14

6 ft

2 ft

8 ft

300 ft 20 ft

12 ft

3 ft

Node numbers

162

Example Two

n Left terminating resistor to node 1 drop line is 20 feet.

n Node 1 drop line is 6 feet. n Right terminating resistor to node 12 drop

line is 2 feet. n Node 12 drop line is 8 feet. n Trunk line from node 12 drop to node 14

drop line is 3 feet. n Node 14 drop line is 12 feet. n Node 1 trunk line to node 14 is 300 feet.

163

Trunk Line Calculation

n For this example, trunk line length is maximum length of cable between any two nodes or terminating resistors.

n Assume round thick trunk line. n Look at network again.

164

Trunk Line Calculation Two (1 of 2)

Power Supply

1

2

3

4

5

6

7 8

9

10

11

12

13

14

6 ft

2 ft

8 ft

300 ft 20 ft

12 ft

3 ft

For this example, trunk line length is maximum length of cable between any two nodes or terminating resistors.

165

Trunk Line Calculation Two (2 of 2)

n The longest cable distance is between the left terminating resistor and node 14.

n For this example, the distance between terminating resistors would not be the correct calculation.

n 20 + 300 + 12 = 332 feet n Refer to table for maximum baud rate of network.

166


Trunk line length is over 328 feet so maximum baud rate for this network is either125 K or 250 k.

167


n The rule is to go back 20 feet from the termination resistors and see if there is a drop line that is longer. Ø If a drop is longer, then it must be included in the trunk line

calculation. Ø Remember maximum drop line length is 20 feet.

168

15

8

4 3

7

20 feet


n Terminating resistor and node 00 is 3 feet.

n Node 00 and node 1 is 4 feet.

n Trunk line to node 7 is 15 feet.

n 15 foot drop is longer than 3 +4 for trunk.

169

Cumulative Drop Line Length (1 of 2)

n Sum of all drop lines n Maximum drop line length to any one node

Ø 20 feet n Cumulative drop line length also determines network baud rate

170

Cumulative Drop Line Length (2 of 2) Text figure 11-30

171

Total All Drop Line Lengths (1 of 2)

172

Total All Drop Line Lengths (2 of 2)

n Cumulative length is 131 feet. n Nodes 10, 13, and 14 exceed the 20-foot maximum drop to any

1 node. n Shorten up cable. n Cumulative drop line length is now 127 feet. n Refer to the table for maximum baud rate for network.

173

Cumulative Drop Line Length

Cumulative drop line length is 127 feet.

174

Power Calculations

n Add up total device current n Determine trunk line length n Cable type n How many power supplies and where

mounted n Look up tables for power allowed on network n Full calculation method available for

additional accuracy

175

Common Problems With DeviceNet Networks (1 of 2)

n Improper installation Ø Trunk line length correct? Ø Cumulative drop line length correct? Ø Power supply proper size? Ø Overdriving network with too much information flow?

n Refer to DeviceNet Cable System Planning and Installation Manual from Rockwell Automation Web site.

176

Common Problems With DeviceNet Networks (2 of 2) n Network modification after installation

Ø Trunk line length recalculated? Ø Cumulative drop line length recalculated? Ø Power supply recalculated? Ø Overdriving network with too much information flow?

177

DeviceNet Interface

178

DeviceNet open-style cable connection point

Set baud rate

Set interface card’s node

Status LEDs

FlexLogix PLC DeviceNet Daughter Card

179

CompactLogix DeviceNet Scanner

DeviceNet scanner Open-style cable connection

CompactLogix processor

CompactLogix is a member of the ControlLogix family.

180

ControlLogix Modular Interface

n ControlLogix modular chassis interface module

n 1756-DNB n DeviceNet bridge module

Information window

Status LEDs

Open-style network connection

1756-DNB

181

Example of Rockwell Automation PLC DeviceNet Interface Modules

n SLC 500 DeviceNet scanner Ø 1747-SDN

n PLC 5 DeviceNet scanner Ø 1771-SDN

182

Example of General Electric PLC DeviceNet Interface Modules

n Series 90-30 PLCs Ø DeviceNet master module Ø IC693DNM200

n VersaMax PLC Ø Remote I/O DeviceNet network interface Ø IC200DB1001

183

Personal Computer DeviceNet Interface

n Computer type determines interface needed. Ø Notebook uses PCMCIA such as a Rockwell Automation

1784-PCD. Ø Desktop or industrial computer would require a DeviceNet

1784-expansion card. Ø Computer with serial port could use Rockwell Automation

1770-KFD interface box.

184

1770-KFD Interface

Desktop or notebook computer with serial port

1770-KFD Interface cable

Open-style connector to DeviceNet network

Interface cable plug

KFD to serial port interface cable

SLC 500 1747-SDN

185

Open-style connector to DeviceNet network

PCMCIA interface card 1784-PCD

SLC 500 1747-SDN Notebook

personal computer Interface cables

1784-PCD Card

186

Use ControlLogix PLC as a Bridge (1 of 2) n Most popular interface to PLC for upload, download, on-line

editing is Ethernet n Ethernet interface card in ControlLogix chassis(1756- ENBT) n A 1756-DNB or DeviceNet bridge module in ControlLogix

chassis to communicate with DeviceNet

187

Use ControlLogix PLC as a Bridge (1 of 2) n Use RSLinx Ethernet driver to get to Ethernet interface module n Bridge across ControlLogix backplane to DeviceNet Bridge

module (1756-DNB) n Out DNB to DeviceNet network n No separate DeviceNet interface required

188

RSNetWorx Software

n RSNetworx for DeviceNet software Ø Set up network Ø Map data flowing on network Ø Program, monitor, or modify device parameters

189

RSNetWorx for DeviceNet

190

RSNetWorx View of DeviceNet



Power supply not shown in RSNetWorx

Trunk line

Drop line

Network scanner

Node address

Device or node on network

191

DeviceNet Scan List

n RSNetWorx software n Scan List is part of scanner properties. n Any device that is on the network that is to

be scanned by the PLC scanner must be in the Scan List.

n Network devices are not mapped until placed in the Scan List by programmer. Ø Auto mapping Ø Manual mapping

192

Add or remove single device to

or from Scan List

Auto map devices when

add to scan list

Scan List tab

Scan List

Electronic keying

ControlLogix DNB scanner

properties screen

DeviceNet PLC Scanner Properties

Add or remove all devices to or from Scan

List

193

Available Devices on Network

n When going on-line with a network scanner, like a 1756-DNB, scanner will recognize devices currently present on network. Ø These devices or nodes will be listed in the Available

Devices view. Ø These devices are not in the scan list at this time.

194

Auto Map Devices When Add to Scan List

n Do you want the device(s) to be auto-mapped when added to the scan list?

n  If Automap is selected, you have no control of how devices are mapped.

n  If you uncheck Automap, then devices can be manually mapped by the programmer.

195

Electronic Keying

n How close does a replacement device have to be to the original when replaced? Ø Device type Ø Vendor Ø Product code Ø Major revision Ø Minor revision

–  Minor revision or higher

196

DeviceNet Data Mapping

ControlLogix

197

ControlLogix 1756-DNB Mapping

Scanner properties

Input devices in Scan List

Input tab

ControlLogix processor tags or addresses

where data is mapped.

Data mapping for each node

Unused processor memory. Can be

manually mapped later.

Click here to unmap a device.

198


n ControlLogix is a 32-bit PLC. Ø All tags will be either 32 bits wide or a:

–  Word, called an integer (INT) which is16 bits –  Byte, called a short integer (SINT) which is 8 bits

n Minimum memory allocation for any DeviceNet device is a SINT.

n Node 6 is a bulletin 160 Allen-Bradley Drive. Ø Drive has two words of data.

–  Drive status information as single bits –  Drive speed feedback represented as 0 to 32767

199

32 Bits

16 Bits 0 7 8 15 16 31

ControlLogix Input Mapping

Node 6 Drive Input Status word

Node 6 Drives Speed Feedback word Node 4 Series 9000 Photo Electric Sensor

mapping

Node 3 Series 9000 Photo Electric

Sensor mapping

ControlLogix Tags

200

ControlLogix Processor Data Mapping or Tags (1 of 2) n Node 6 is Bulletin 160, the variable frequency drive

Ø Status bits mapped as upper word of Local:1:I.Data[2]. Ø Drive Speed Feedback word is mapped as the lower word of

Local:1:I.Data[3].

201

ControlLogix Processor Data Mapping or Tags (2 of 2) n Node 4 is a Series 9000 Photo Switch mapped as the upper byte

of the lower word at Local:1.I.Data[2]. n Node 3 is a Series 9000 Photo Switch mapped as the lower byte

of the lower word at Local:1.I.Data[2].

202


SLC 500

203


n SLC 500 and PLC 5 are 16-bit computers. Ø All data will either be a 16-bit word or one byte.

n Minimum memory allocation for any DeviceNet device is a byte.

n Node 6 is a Bulletin 160 Allen-Bradley Drive. Ø Drive has two words of data.

–  Drive Command information as single bits –  Drive Speed Command represented as 0 to

32767

204

SLC 500 Output Data Mapping

1747-SDN properties view

Output devices in Scan List

SLC 500 Output Status Table where data is

coming from

Output mapping tab

Click here to unmap selected device

Two words or 8 bytes currently

mapped for drive at node 6

205

SLC 500 Processor Data Mapping

n Node 6 is Bulletin 160, the variable frequency drive Ø Drive Command bits word is mapped as O:1.2. Ø Drive Speed Command word is mapped as O:1.3.

206

Node 2 Output Mapping

n Node 8 is a Rockwell Automation 1792D compact block output module. Ø This compact block has four outputs.

n Output data from SLC 500 mapped to lower byte of O:1.6. n Currently upper byte of O:1.6 is available for another device.

207

DeviceNet Nodes General Properties

208

n Right click on device on RSNetWorx screen. n General Properties screen is displayed.

Ø Display I/O data Ø Display, monitor, or modify devices parameters Ø View electronic data sheet (EDS file)

209

Identifies this device

Current node address. Node address can be

changed here.

Parameters tab

Device’s identity

EDS tab

Numbers used to identify EDS file

General Properties

210

Device Parameters

Parameters tab

Parameter number

Lock identifies read-only

parameters Click here to monitor parameter

Icons for uploading or downloading

to device

Monitor a single parameter or all

Current value of parameter

Device

211

Parameter Editing

Select parameter to edit

Options drop-down box

Select

212

Electronic Data Sheets

EDS Files

213

Electronic Data Sheets

n Typically referred to as EDS files Ø EDS files contain information regarding the personality of the

device. Ø Correct EDS file must reside in the device before it can be a

working part of the network. Ø EDS file must be the same firmware level as the device.

214

If EDS File Is Not Current

n Go to manufacturer’s Web site and download correct file. n Go to ODVA.ORG site and download correct file. n EDS file numbers represented in Hex. n Use EDS Wizard to update or register the network device.

215

EDS Wizard

Updating a network Device’s EDS file is to

register the file.

Click next to continue.

216

Register EDS File

How many files to register

After download, browse for file

on you computer.

Click next to continue

registration.

EDS file name represented

in Hex

217

Determine EDS File Name

n After downloading EDS file, the file name is represented in Hex. Ø To determine EDS file to use when registering file:

–  Must know Hex –  Construct file number from RSNetWorx general properties

page

218

[1] = 0001

Convert General Properties Page Device Identity to Hex

[6] = 0006

[43] = 002B

[1.004] = 0100

219

Select Correct EDS File

220

Select Correct EDS File

221

DeviceNet

Typical Applications: Most commonly found in assembly, welding and material handling machines. Single-cable wiring of multi-input sensor blocks, smart sensors, pneumatic valves, barcode readers, drives and operator interfaces. DeviceNet is especially popular in automotive and semiconductor.

222

DeviceNet

Advantages: Low cost, widespread acceptance, high reliability, and efficient use of network bandwidth, power available on the network. Disadvantages: Limited bandwidth, limited message size and maximum length

223

DeviceNet

Versatile, Available, and Competitive DeviceNet is a versatile, general purpose Fieldbus designed to satisfy 80% of the most common machine- and cell-level wiring requirements. Devices can be powered from the network so wiring is minimized. The protocol is implemented on many hundreds of different products from hundreds of manufacturers, from smart sensors to valve manifolds and operator interfaces.

224

DeviceNet

Versatile, Available, and Competitive One of DeviceNet's major benefits is its multiple messaging formats, which allow the bus to 'work smart' instead of work hard. They can be mixed and matched within a network to achieve the most information-rich and time-efficient information from the network at all times:

225

DeviceNet

Messaging Types in DeviceNet Polling: The scanner individually asks each device to send or receive an update of its status. This requires an outgoing message and incoming message for each node on the network. This is the most precise, but least time efficient way to request information from devices.

226

DeviceNet

Messaging Types in DeviceNet Strobing (broadcast): The scanner broadcasts a request to all devices for a status update. Each device responds in turn, with node 1 answering first, then 2, 3, 4 etc. Node numbers can be assigned to prioritize messages. Polling and strobing are the most common messaging formats used.

227

DeviceNet

Messaging Types in DeviceNet Cyclic: Devices are configured to automatically send messages on scheduled intervals. This is sometimes called a 'heartbeat' and is often used in conjunction with Change of State messaging to indicate that the device is still functional.

228

DeviceNet

Messaging Types in DeviceNet Change of State: Devices only send messages to the scanner when their status changes. This occupies an absolute minimum of time on the network, and a large network using Change of State can often outperform a polling network operating at several times the speed. This is the most time efficient but (sometimes) least precise way to obtain information from devices because throughput and response time becomes statistical instead of deterministic.

229

AS-I (Actuator Sensor Interface)

230


AS-I (Actuator Sensor Interface) - simple and inexpensive fieldlevel network. • Origin: AS-I Consortium, 1993 • Maximum Number of Nodes: 31 slaves, 1 master • Connectors: Insulation displacement connectors on flat yellow cable, 2 position terminal block or 12mm ‘micro’ quick-disconnect connectors. • Distance: 100M, 300M with repeaters

231


• Baudrate: 167 Kbits/sec • Message size: 8 bits (4 inputs, 4 outputs) per node per message • Messaging formats: Strobing

232


• Typical Applications: Commonly found in assembly, packaging and material handling machines. Single-cable wiring of multi-input sensor blocks, smart sensors, pneumatic valves, switches and indicators. • Advantages: simplicity, low cost, widespread acceptance, high speed, power available on the network. AS-I is extremely suitable for wiring discrete I/O devices. • Disadvantages: problems when connecting analog I/O; limited network size;

233


ASI is developed by a consortium of European automation & sensor companies, which saw a need for networking the simplest devices at the lowest level. ASI is easy to configure and low in cost. It is most often used for proximity sensors, photo-eyes, limit switches, valves and indicators in applications like packaging machines and material handling systems. ASI is designed for small systems employing discrete I/O. It allows for up to 31 slaves, which can provide up to 4 inputs and 4 outputs each for a total of 248 I/O. ASI is arguably the simplest Fieldbus to use. ASI uses number of sophisticated and clever mechanisms to ensure fast and reliable data transmission and user friendliness. The only configuration issues are choosing the address of each node and assigning individual inputs and outputs within those nodes.

234


The flat yellow cable ASI is best known for its flat yellow cable, which is pierced by insulation displacement connectors so that the expense of tees and complex connectors is avoided. Devices are simply clamped onto the cable and a.connection is made. In addition to the popular flat cable, ordinary lamp cord can be used and normally no adverse effects will be experienced. Power on the bus The signal cable also carries 30VDC at low current to power input devices; supplemental power for outputs can be provided via an additional flat (black) cable. Most output devices have provisions for this extra cable.

235


Analog I/O Analog signals can be transmitted on ASI, but a node can represent only one analog device, and fragmented messaging must be used to transmit signals requiring more than 4 bits. Determinism and Scan Time ASI is deterministic; meaning that one can know with certainty how long it will take for status changes to be reported to the master. To calculate scan time, multiply the number of nodes (including the master) by 150 microseconds. The maximum network delay is 4.7mS, which is certainly speedy enough for most applications (most PLC's have a scan time of 20mS or more!).

236


Analog I/O Analog signals can be transmitted on ASI, but a node can represent only one analog device, and fragmented messaging must be used to transmit signals requiring more than 4 bits. Determinism and Scan Time ASI is deterministic; meaning that one can know with certainty how long it will take for status changes to be reported to the master. To calculate scan time, multiply the number of nodes (including the master) by 150 microseconds. The maximum network delay is 4.7mS, which is certainly speedy enough for most applications (most PLC's have a scan time of 20mS or more!).

237

CONTROLNET

238

CONTROLNET

CONTROLNET - mission critical control-level network • Origin: Allen-Bradley, 1995 • Based on RG6/U cabling (popular in cable TV applications) and • Rockwell ASIC chip • Maximum Number of Nodes: 99 • Connectors: Twin redundant BNC • Maximum Distance: 250 to 5000M (with repeaters) • Baud rate: 5M bit/Sec • Message Size: 0-510 bytes • Messaging Formats: Based on Producer/Consumer model; multi-master, peer to peer, fragmented, prioritized and deterministically scheduled repeatable messages; dual transmission paths for built-in redundancy.

239

CONTROLNET

• Typical Applications: Mission critical, plant-wide networking between multiple PC’s, PLC’s and sub-networks (i.e. DeviceNet, Foundation FieldBus H1, etc.) and process control, and situations requiring high-speed transport of both time-critical I/O and messaging data, including upload/download of programming and configuration data and peer-to-peer messaging. • Advantages: Deterministic, repeatable, efficient use of network bandwidth, provides redundancy at lower cost than most other available networks including Ethernet. Can be transmitted on any IP transport protocol via Ethernet, Firewire or USB.

240

CONTROLNET

Disadvantages: Limited multi-vendor support and expensive Rockwell ASICs (Application-Specific Integrated Circuits). ControlNet was conceived as the ultimate high-level Fieldbus network, and was designed to meet several high-performance automation and process control criteria. Of primary importance is the ability of devices to communicate to each other with 100% determinism while achieving faster response than traditional master/slave poll/strobe networks. (Determinism means knowing absolute worst-case response times with 100% certainty.) This is made possible by the Producer/Consumer communication model and the scheduler, which rigorously prioritizes messages.

241

CONTROLNET

Multi-Master and repeatability ControlNet allows multiple masters to control the same I/O points. Repeatability ensures that transmit times are constant and unaffected by devices connecting to, or leaving, the network. These features are further enhanced with user selectable I/O and controller interlocking update times to match application requirements.

242

CONTROLNET

Large quantities of data and complex devices. ControlNet is specifically designed to accommodate the high-level information and control needs of literally dozens of sub-networks and controllers. In process control situations where hazardous materials are involved and absolute certainty with respect to control processes is required, the deterministic capabilities of ControlNet are extremely important. Redundancy The ControlNet architecture has redundant connectivity as an integral feature. Redundancy is rather difficult to achieve with other networks, but each ControlNet node has dual connections for this very purpose.

243

Networks Popularity

n Stand-alone PLCs fading fast n Older networks being upgraded

Ø Faster more efficient networks Ø New networks offer deterministic and repeatable data

transfer

244

Network Advantages for Maintenance Individuals

n PLCs connected on network Ø Access any PLC from a single computer anywhere on the

network Ø Upload, download, on-line editing across network to any

device on network from a central location

245

ControlNet

n Open network managed by ControlNet International

n Use for real-time data transfer of time-critical and non-time-critical data between processors or I/O on same link

n Data transferred at a fixed rate of 5 million bits per second

n ControlNet basically a combination of Allen-Bradley’s Data Highway Plus and Remote I/O

246

ControlNet Nodes

n Up to 99 nodes n No node 0 n Actual number of nodes determined by how efficiently the

network bandwidth is set up n Network set up using RSNetWorx for ControlNet software

247

Nodes on ControlNet

n SLC 500, ControlLogix, PLC 5 processors n Third-party field devices n Operator interface n Variable frequency drives

248

ControlNet Applications

n ControlLogix processor, SLC 500, or PLC 5 processor scheduled data exchange

n Local PLC connection to remote chassis for high-speed remote I/O connectivity

249

Interlocking or Synchronization of Multiple Nodes

n Synchronized starting of variable frequency drives on ControlNet n  Interlocking multiple processors

250

Network Bridging

n Connect two Data Highway Plus networks n Connect multiple DeviceNet networks

251

Trunk Line – Drop Line

Node number


Control Net Tap

Trunk line

Drop line


PLC 5 as node 7

SLC 500 as node 8 Variable

frequency drive as node 4

Computer Interface cards

Operator interface

ControlLogix PLCs

252

ControlNet Taps

Straight T Straight Y Right Angle Right Angle Y

Drop line length is fixed at 1 meter (39.5 inches).

253

SLC 500 ControlNet Interface

n 1747-SCNR n SLC 500 modular PLCs n Scheduled and unscheduled

messaging

254

ControlLogix ControlNet Interface

n 1756-CNB Ø Channel A only

n 1756-CNBR Ø Channel A and B for

redundant media n Module node address set

with side switches n Duplicate node addresses

not allowed n NAP for computer

connectivity

255

FlexLogix ControlNet Interface

FlexLogix processor

Two communication card slots

Two ControlNet interface cards with redundancy

NAP

Set node address here

256

Redundant Media

Tap

Trunk line

PLC 5 node

Personal computer with ControlNet

interface

Redundant cables

Drop line

ControlLogix

257

258

Personal Computer Interface

Personal computer with ControlNet interface card like 1784-KTCX15

Redundant trunk line

259

KTCX15 ControlNet Interface

Status indicators Network access port

Channel A

Channel B

Floppy with card driver

260

KTCX15 Interface to PLC 5

PLC 5 ControlNet processor

NAP

Channel A

Channel B

Redundant

trunk line

261

Redundant trunk line

Personal computer with ControlNet interface

NAP connection

Personal Computer to NAP

262

ControlNet Cabling

ControlNet Segment

263

Cabling Terms

n Segment n Trunk line cable section n Termination resistor n Link

264

Segment

n Comprised of a number of sections of trunk cable separated by taps

n Maximum segment length 1,000 meters or 3,280 feet n Maximum 48 nodes per segment n Segment length determined by number of nodes

265

Taps

n Taps are required. n There is no minimum cable length between taps. n Taps can be directly connected together.

266

Trunk Line Cable Section

n Trunk line cable section connects one tap to another. n Taps are required. n Standard light industrial quad shielded RG-6. n Special use cables are available. n Fiber optic cables are available.

267

Termination Resistor

n One termination resistor is required on the end of every segment.

268

ControlNet Segment

Termination resistor Termination

resistor 39.5

inches

Segment

Trunk line Drop

line Tap

269

Segment Calculation

n Formula to calculate segment length

1,000 meters – [16.3 meters ( number of taps – 2)]

270

Calculation Example:

n Calculate maximum segment length using standard light industrial RG-6 coax requiring 22 taps.

1,000 meters – [16.3 meters ( 22 - 2)]

1,000 meters – [16.3 meters ( 20 )]

1,000 meters – 326 meters

Maximum segment length = 674 meters

271

ControlNet Link

n  If more than 48 nodes are required, an additional segment is required.

n Repeater connects segments. n Two segments connected by a repeater is a link.

272

Three Segments Connected by a Repeater to Create a Star

273

Four Segments Connected by Repeaters to Create a Ring

274

ControlNet Repeaters

n Required if additional nodes are required after either maximum number of nodes or cable length reached

n Two modules required to build a repeater n Many copper and fiber repeaters to select from depending on

application

275

Building a Repeater Example

n The two repeater modules can be DIN rail-mounted as a pair to build a repeater. Ø 1 - 1786-RPA (repeater adaptor module) Ø 1 - 1786-RPCD (dual copper repeater)

276

Repeater Adapter Module

277

Dual Copper Repeater Module

278

Repeaters

ControlNet PLC 5

Add Flex- I/O blocks to this communication for remote I/O points

279

Example of Fiber Repeater

n Fiber repeaters available as short, medium, long, and very long haul

n Up to 18.5 miles ControlNet network using proper fiber repeaters

n Right-hand module in previous slide

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RSNetWorx Software

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RSNetWorx

n From Rockwell Software n Required to configure and schedule a ControlNet network

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RSNetWorx For ControlNet

Graphic view of network

Go on-line with network

RSNetWorx for ControlNet

Enable editing

Manual network

configuration

Network bandwidth utilization

Trunk line

Node number

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How Critical is this Data?

n Separate data into two categories. Ø Is this information time critical? Ø Can this information be transferred on a non-time critical

basis?

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What is Real-Time for This Application?

n How soon do you really need the information? n Networks do not have unlimited bandwidth.

Ø Cannot have everything instantly

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Realistic Data Flow (1 of 2)

n Assume you had a tank that takes four hours to fill. Ø Why would you need a tank level every 10 milliseconds? Ø What is realistic? Ø Would every few seconds be acceptable?

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Realistic Data Flow (2 of 2)

n Assume you had a tank of water that takes two hours to heat. Ø Why would you need a tank temperature every 10

milliseconds? Ø What is realistic? Ø Would every few seconds be acceptable?

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Scheduled / Unscheduled

n Time critical data is scheduled data. Ø Requested packet interval (RPI) set up in RSNetWorx

n Non-time critical data is unscheduled data. Ø Message instruction programmed on PLC ladder rung

–  Trigger to transfer only when needed

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RPI

n Requested packet interval n Scheduled network service

Ø The requested interval time-critical data will flow Ø ControlNet will meet or beat the RPI if network installed and

configured properly

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Inefficient Network

n  Improper installation Ø Follow installation manual

n  Improper network modification Ø Follow installation manual

n Poor design Ø Follow installation manual

n Overdriving network Ø Unrealistic data flow expectations

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ControlNet Bandwidth

n Three pieces to bandwidth Ø Scheduled traffic Ø Unscheduled traffic Ø Maintenance or guard band

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Scheduled Traffic Unscheduled

Traffic Network Maintenance

Network Update Time

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Network Update

n One cycle of the network n Called NUT time

Ø Set up on RSNetWorx n Data cannot transfer faster than the NUT

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Scheduled Maximum Node

n SMAX n This is the highest node number that will be allowed to send

scheduled data. n Any node address above SMAX that has scheduled data to

transfer will not be allowed to transmit.

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Unscheduled Maximum Node

n UMAX n This is the highest node number that will be allowed to send

unscheduled data. n Any node address above UMAX that has scheduled data to

transfer will not be allowed to transmit.

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Node Can Send Both

n A node can send scheduled as well as unscheduled data/ n The node number must be within SMAX.

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Slot Time

n Slot time is time the network spends waiting for a node to respond when the node address is either not used or the node is not responding.

n Unused node addresses should be kept to a minimum for network efficiency.

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NUT

SMAX

UMAX

Media and channel information

RSNetWorx Parameters

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Set-up Example

n 10 nodes scheduled traffic n 2 spare nodes future scheduled traffic n 14 unscheduled nodes n 3 nodes for NAP connectivity

Ø What will SMAX be? Ø What will UMAX be? Ø What about slot time? Ø Maximum cable length?

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Maximum Segment Length

n Assume RG-6 coax Ø How many taps?

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Number of Taps

n Number of taps does not include NAP connections. n No node 0 in ControlNet. n To keep it simple, let’s use taps as nodes 1 to 26.

Ø NAP nodes 27, 28, 29 Ø Total taps = 26

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Segment Calculation

n 1,000 meters – [16.3 meters( Number of taps – 2)] n 1,000 meters – [16.3 meters( 26 – 2)] n 1,000 meters – [16.3 meters( 24 )] n 1,000 meters – 391.2 meters n  Maximum segment length 608.8 meters

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SMAX

n Scheduled traffic nodes 1- 12 n Nodes 1-10 currently used n Nodes 11 and 12 future scheduled

Ø Unused nodes = slot time n SMAX set at 12

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Determine UMAX

n Nodes 13 - 26 unscheduled traffic n Nodes 27, 28, 29 for NAP

Ø RSLinx drivers for personal computer node addresses MUST be set at 27, 28, or 29.

Ø RSLinx default for 1784-PCC personal computer interface default = node 99.

n UMAX must be set at a minimum of 29.

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Efficient Network Configuration

1 99

UMAX =29 SMAX= 12

Node 10 Node 11 & 12

future scheduled Node 27, 28, 29

for NAP

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Future Network Expansion

n Recalculate segment length? n Reconfigure SMAX? n Reconfigure UMAX? n Reschedule network using RSNetWorx if any scheduled node is

added or modified.

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Reschedule Network

n  It must be done whenever a scheduled node is modified or added to the network.

n Network configuration is scheduled in RSNetWorx for ControlNet. Ø Part of saving new network configuration Ø ALL processors on network in program mode Ø Referred to as optimizing and rewriting network configuration

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Rescheduling and the Keeper

n The ControlNet communication module at the lowest node number is called the keeper. Ø Should be node 1 Ø For ControlLogix 1756-CNB(R) Ø Keeper like a traffic cop

–  Directs traffic on network and synchronizes nodes Ø Newer CNBs have multi-keeper capability

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Multi-keeper

n Older CNBs are single-keeper networks. Ø Newer CNBs support multi-keeper. Ø If there was a newer CNB at node 1 and also at node 2,

node 1 would be the keeper and node 2 would be a “back-up” keeper.

Ø If node 1 fails, node 2 would take over network traffic control. Ø In single-keeper systems, if the keeper fails, all network

communications are lost.

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ETHERNET

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ETHERNET

Ethernet: the worldwide de facto standard for business and PC Networking • Origin: Digital Equipment Corporation, Intel and Xerox, 1976 • Implemented on Multitudes of chips produced by many vendors. Based on IEEE 802.3 • Formats: 10 Base 2, 10 Base T and 100 Base T, 100 Base FX, 1 Gigabit; Copper (Twisted Pair / Thin Coax) and Fiber • Connectors: RJ45 or Coaxial • Maximum Number of Nodes: 1024, Expandable with Routers • Distance: 100M (10 Base T) to 50 KM (Mono mode, Fiber with Switches) • Baudrate: 10M to 100M Bit/sec • Message size: 46 to 1500 bytes • Messaging format: Peer-to-Peer

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ETHERNET

• Typical Applications: Nearly universal in office / business Local Area Networks. Widely used also in PC to PC, PLC to PLC and supervisory control applications. After 2000 Ethernet is gradually working its way toward the “sensor level” in plant floor applications.

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ETHERNET

• Advantages: Ethernet is the most widely accepted international networking standard. Nearly universal worldwide. Ethernet can handle large amounts of data at high speed and serve the needs of large installations. • Disadvantages: High overhead to message ratio for small amounts of data; No power on the bus; Physically vulnerable connectors and greater susceptibility to EMI/RFI than most fieldbuses; Confusion based on multiple open and proprietary standards for process data.

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ETHERNET

The networking of millions of PC’s in offices and the proliferation of the Internet across the world has made Ethernet a universal networking standard. Ethernet hardware and related software has evolved to the point where even inexperienced users can build simple networks and connect computers together. Ethernet hardware is cheap and can be purchased in office supply stores, computer stores and e-commerce sites. A study by an automotive manufacturer showed that Ethernet could potentially serve up to 70% of plant floor networking applications. But there are at least four major issues, which must be addressed satisfactorily for Ethernet to become a viable, popular, plant-floor network:

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ETHERNET

1. A common “Application Layer” must be established. When our device receives a packet of data, what format is that data in? Is it a string of I/O values, a text document or a spreadsheet? Is it a series of parameters for a Variable Frequency Drive? How is that data arranged? There are several competing standards resolving this issue. 2. Industrial grade connectors will be necessary for many applications. Cheap plastic “telephone connectors” and the RJ45 connectors are not suitable for the plant floor; industrial strength connectors are needed. 3. Many users desire 24 Volt power on the Bus (like DeviceNet is). This is advantageous from a practical standpoint – it reduces wiring and power supply problems -- but it adds cost and introduces noise and other technical problems.

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ETHERNET

4. Some applications require determinism. Ethernet - as it is typically used - is not deterministic or repeatable; in other words, throughput rates are not guaranteed. However, methods exist for architecting.deterministic Ethernet systems. In reality, most applications don't need determinism - they just need speed.

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ETHERNET

There are many transmission protocols that can be used on Ethernet. The most popular, and the one used on the World Wide Web, is TCP/IP, which stands for Transmission Control Protocol/Internet Protocol. When we download a file from the web, we can see the speed of the transmission speed up and slow down as network traffic levels change. TCP/IP is the mechanism that breaks the downloaded file into any number of bits and pieces and re-assembles them at the other side. TCP/IP was developed at Stanford University in the 1970’s as a “handshaking” mechanism that would assure that ‘the message would always eventually get through.’

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ETHERNET

To carry the Web example a bit further, we’ve all had the experience of downloading a large file, only to discover that our PC “cannot find an associated application for this file type.” So we end up downloading a plug-in like Shockwave or RealAudio or Winamp or Adobe Acrobat Reader so we can open the file. The exact same problem applies to industrial controls. We can send any file or piece of process data we want to over Ethernet or the Internet, but the receiving end has to know what to do with the data. TCP/IP doesn’t assure we of opening the file; it just guarantees that it will arrive.

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ETHERNET

Existing fieldbuses on Ethernet. The next frontier for the established fieldbus organizations is to produce Ethernet TCP/IP application layers of their protocols. Presently, there are four major contenders: Modbus/TCP (Modbus protocol on TCP/IP), EtherNet/IP (the ControlNet/DeviceNet objects on TCP/IP), Foundation Fieldbus High Speed Ethernet, and Profinet (Profibus on Ethernet). One could propose an infinite number of potential application layer protocols, and in fact right now there are, in addition to the above protocols, a myriad of other, proprietary standards from various vendors.

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ETHERNET

Existing fieldbuses on Ethernet. But there are several significant advantages to employing the existing bus architectures: • Profiles for many devices have already been defined, and can be transferred to Ethernet with relatively little effort. • In systems which use, for example, Profibus as an I/O level network, and Profibus on Ethernet at the supervisory level, the relationship between the two networks is relatively transparent. Data can be transferred between the upper and lower network fairly easily. • Many developers and users are familiar with these existing protocols, and this speeds the process of product development and adoption.

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ETHERNET

Existing fieldbuses on Ethernet. But there are several significant advantages to employing the existing bus architectures: • Profiles for many devices have already been defined, and can be transferred to Ethernet with relatively little effort. • In systems which use, for example, Profibus as an I/O level network, and Profibus on Ethernet at the supervisory level, the relationship between the two networks is relatively transparent. Data can be transferred between the upper and lower network fairly easily. • Many developers and users are familiar with these existing protocols, and this speeds the process of product development and adoption.

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EtherNet/IP Profile Switch Step by Step

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Agenda

n Commercial Information n  Integrating the EtherNet/IP Profile Switch

Ø Assign IP address Ø Enable EtherNet/IP and register EDS files Ø Using RSLogix5000 sample files (v16 required) Ø Using RSView Studio sample files

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Commercial Information

n The EtherNet/IP Profile is available in the 3.0 firmware release for all Open Rail switches (RS20/30/40 and MS20/30)

n This functionality allows the switch to be integrated directly into the RSLogix5000 I/O tree

n There is no additional cost n Switches already in the field can be flashed to

this firmware level (firmware can be found at ftp.hirschmann-usa.com/firmware or send e-mail to [email protected])

n 3.1 release (June) will add support for MACH, PowerMICE and Octopus families

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Integrating the EtherNet/IP Profile Switch Step 1 – Assigning IP Address to a new switch

n Use HiDiscovery to set the switch’s IP address & subnet mask n HiDiscovery is on the product CD or can be downloaded at

ftp.hirschmann-usa.com/software

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Step 2 – Enable EtherNet/IP and register EDS files

n Connect to the switch with your web browser – answer Yes when prompted

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Step 2 - continued

n Login as “Admin”, default password is “private”

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Step 2 - continued

n Expand the “Advanced” menu item, and select “Industrial Protocols”

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Step 2 - continued

n Click the box to enable EtherNet/IP n Click the Set button at the bottom of the page

*** Be sure to go to the Load/Save screen, and Save your configuration to make this change permanent.***

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Step 2 - continued

n Click on the Download EDS File button (the EDS file is generated dynamically based on the switch’s product code, then transferred to your PC)

n Register the EDS file using the EDS Hardware Installation Tool (Start > All Programs > Rockwell Software > RSLinx Tools > EDS Hardware Installation Tool)

n Alternately, all EDS files are included on the product CD. You can register them all at once from there.

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Step 3 – using RSLogix5000 sample files

n Sample files are available at http://samplecode.rockwellautomation.com (search Title – Hirschmann) or at ftp.hirschmann-usa.com/EthernetIP

n Version 16 is required for this file – it takes advantage of the new Add-On Instruction functionality

n Version 16 is NOT required for the EtherNet/IP functionality of the switch to work – only to use these sample files

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Step 3 - continued

n You can use the base sample file or import the Add-On Instruction from the XML file into an existing project (right click on Add-On Instructions, and import)

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Step 3 - continued

n Add a Generic Ethernet module to the I/O tree n Enter the IP address n Set the Connection Parameters as shown below n Set the RPI to 100

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Step 3 - continued

n Click the Add-On tab on the Instruction Bar n Add the Hirschmann Instruction to your ladder program

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Step 3 - continued

n Enter a name for this switch in the “Hirschmann_Switch” field (datatype = Hirschmann_Switch)

n Map the Switch_Inputs and Switch_Output as shown below: Ø Switch_Inputs – Name of the switch created:I.Data Ø Switch_Output – Name of the switch created:O.Data[0]

n Enter & create tags as shown below: Ø Switch_Parameters (Datatype = Switch_All) Ø GetMessage (Datatype = Message) Ø Set Message (Datatype = Message) Ø Storage fields (Datatype = SINT[200]

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Step 3 - continued

n Your instruction should now look something similar to this

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Step 3 - continued

n Configure the GetMessage as shown below

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Step 3 - continued

n Configure the SetMessage as shown below

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Step 3 - continued

n For both Message instructions, click on the Communication tab, then click browse

n Select the appropriate switch from the I/O tree

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Step 4 – Using RSView Studio sample files

n Open your RSView Studio application n Make sure the communication path is set up to your PLC n Right click on Global Objects – then select Import and Export n Click No – do not backup displays, then click next n Select Multiple Displays Import File, then click next n Click on the … to open the file browser and point to the file

called BatchImport_Hirschmann Switch.xml n Make sure that create new objects is selected n Click Finish

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Step 4 - continued

n Your project tree should now show a number of new global objects

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Step 4 - continued

n Right click on Parameters and select New n Enter an expression similar to the one shown below n  [Switch_Text] is the RSLinx Enterprise shortcut to the PLC n My RailSwitchParams is the name of the tag in the Switch

Parameters field of the RSLogix5000 Add-On Instruction

RSLinx Enterprise shortcut to the PLC

Tag name from RSLogix5000

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Step 4 - continued

n Save and close the parameter file n Creating the graphics

Ø You will have 1 overview screen for each switch in your application

Ø You only need to create the “Pop Up” screens once, they will represent the appropriate information using the Parameter files

Ø Create the 5 “pop up” displays •  Diagnostics •  Configure IGMP •  Configure Ports •  Switch Information •  Port Stats

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Step 4 - continued

n To create a Switch Overview Display: Ø Select the appropriate Global Object

for your particular switch Ø Edit the 5 buttons so that the

appropriate Parameter file is used for the Pop Up screens

Ø Save the file (but leave it open) Ø Create a new display Ø On the Global Object file, click Edit >

Select All, then drag the objects to your new display

Ø Save your new display Ø Make sure to include the Parameter

file in the button that calls the Switch Overview screen

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Step 4 - continued

n Before running your project, you will need to create 2 HMI memory tags Ø Name: PLC_Port_Number and PC_Port_Number Ø Type: Analog Ø Initial Value: 0

n These tags are used on the Ports screen n You will get error messages if they are not created

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Step 4 - continued

n The result should look similar to the following screenshots n HINT: The Parameter files don’t initialize in Test Run mode

– you have to actually run the project to test your screens

Overview Screen for an RS20-16

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Step 4 - continued

Diagnostics Screen

Read Only Provides information found on the Diagnostics screen in the

web interface. Some of these alarms are disabled by default.

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Step 4 - continued

Switch Information Screen

Read Only Provides information found on the Main screen in the web

interface.

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Step 4 - continued

IGMP Settings Screen

Read/Write Provides information found on the Multicast screen in the web interface. Users can Enable/Disable IGMP snooping

and querier mode and set the IGMP protocol version (default is 2).

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Step 4 - continued

Port Settings Screen

Read/Write Users can Enable/Disable each port of the switch

individually. If you click the “PLC Port” button, you can enter a port number that cannot be disabled.

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Step 4 - continued

Port Statistics Screen

Read Only Provides information on an individual port. Click on the Port

button to select the port that you want information on.

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Step 4 - continued

Disclaimer

Please keep in mind that these are sample files – provided to make it easier for users to integrate the Hirschmann EtherNet/IP

Profile Switches into their applications.

Careful thought should be given as to how to integrate these files. It is recommended that you password protect or disable some

screens to prevent unauthorized access.

The applications should be thoroughly tested and verified before being deployed in a production environment.

Documents

PLC Network