IBM Ethernet TCP/IP Adapter Module CTI 2572 manual

CTI 2572 ETHERNET TCP/IP ADAPTER MODULE TECHNICAL OVERVIEW Version 1.1 CTI Part # 062-00156 '#("#' 2572 Techni cal Overvi ew Manua l 032698 $25[...]

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CTI 2572 Technical O v erview Manual Copyright 1993, 1998 Control Technology Inc. All rights reserved . This manual is published by Control Technology Inc., 5734 Middlebrook Pike, Knoxville, TN 37921. This manual contains references to brand and product names which are tradenames, trademarks, and/or registered trademarks of Control Technology Inc. [...]

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CTI 2572 Technical O v erview Manual i PREFACE This Technical Overvi ew Manual provides an introduction to CTI 2572 Ethernet TCP/IP Adapter and to the networking specifications used with the module. The manual is intended for those individuals who wish to gain a fundamental understanding of the 2572, Ethernet, TCP/IP, and SIMATIC TI505 PLC command [...]

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CTI 2572 Technical O v erview Manual iii TABLE OF CONTENTS CHAPTER 1. I NTRODUCTI ON .................................................................................................. 1 1.1 Description ........................................................................................................................... 1 1.2 2572 Functions ...[...]

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CTI 2572 Technical O v erview Manual v TABLE OF FIGURES Figure 1 CTI 2572 .......................................................................................................................... 1 Figure 2 Token Ring Topology....................................................................................................... 4 Figure 3 Ethernet[...]

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CTI 2572 Technical O v erview Manual 1 CHAPTER 1. INTRODUCTION 1.1 Description The 2572 Ethernet TCP/IP Adapter is a single wide I/O module which connects SIMATIC TI505 controllers to Ethernet networks. Using TCP/IP (Transmission Control Protocol/ Internet Protocol), other controllers or computers can access registers, counters, timers, and memory [...]

CTI 2572 Technical O v erview Manual 2 1.2 2572 Functions Server Mode In Server Mode , the module responds to PLC commands embedded in the TCP/IP packet. The initiating device (usually a computer or a 2572 operating in client mode) encapsulates the PLC command in the TCP/IP protocol and transmits it to the IP address of the 2572. The 2572 retrieves[...]

CTI 2572 Technical O v erview Manual 3 CHAPTER 2. LOCAL AREA NETWORK OVERVIEW Local Area Networks (LANs) gre w from the need to interconne ct many intelligent devic es in a non-proprietary manner. Today, the most widely used LAN standards are Token-Ring (IEEE 802.5) and Ethernet (IEEE 802.3). Token Bus (IEEE 802.4), was proposed by GM in the late 8[...]

CTI 2572 Technical O v erview Manual 4 2.2 IEEE 802.5 (Token-Ring) Token Ring (IEEE 802.5) uses a ring topology. Each station on the network has two connections - one to the "downstream" station and one to the "upstream" stations. Each station receives network data from th e downstream station and passes it to the upstream stati[...]

CTI 2572 Technical O v erview Manual 5 2.3 Ethernet and IEEE 802.3 Officially, "Ethernet" is the name of a CSMA/CD network developed at Xerox. It was jointly documented by Digital Equipment Corporation (DEC), Intel, and Xerox in a 1982 specification for Ethernet Version 2. This specification is commonly called Ethernet II or "Blue Bo[...]

CTI 2572 Technical O v erview Manual 6 The primary disadvantage of Ethernet is that the response time is not consistent under widely varying loads. As the network loading increases above 50% , collisions occur more frequently and the network response time increases. In practice, most large busy networks use bridges to reduce the number of c ollisio[...]

CTI 2572 Technical O v erview Manual 7 2.6 Summary Older master/slave networks are rapidly bei ng replaced by standard LANs which provide better performance, multi-vendor support, and integration with information networks. Of the current LAN standards, Token-Ring and Ethernet have the si gnificant market share. Token Bus, because of the cost and co[...]

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CTI 2572 Technical O v erview Manual 9 CHAPTER 3. ETHERNET OVERVIEW 3.1 ISO Reference Model Modern network implementations separate data communication functions into layers. Each layer performs a specific set of services and interacts with layers above and below in a well defined way. In 1984 the International Standards Organization published the O[...]

CTI 2572 Technical O v erview Manual 10 3.2 Ethernet Topologies and Media - Physical Layer Ethernet Version 2 and IEEE 802.3 are fully compatible at the physical level. Therefore the formal IEEE 802.3 specification is used to describe all Ethernet media. The 802.3 specification provides for a variety of topologies and media. All commonly used media[...]

CTI 2572 Technical O v erview Manual 11 Although 10Base2 cabling avoids the expense of a hub, it presents a major disadvantage for large installations. Because "T" connectors are used at each tap, there are two connections to the main cable for each node. Should a problem develop with the "T" connection, communications between s[...]

CTI 2572 Technical O v erview Manual 12 FOIRL (Fiber Optic) Like the 10BaseT standard, the fiber optic cabling scheme uses a hub technology. Network stations are connected to the hub via point to point fiber optic connections. The fiber optic cable is attached to the network adapter using transceivers connected to the AUI port. A fiber optic cable [...]

CTI 2572 Technical O v erview Manual 13 Mixed Media Multiple media types ma y be used on the same network. In larger installations it is very co mmon for distributed 10baseT hubs to be interconnected via a fiber optic hub. The fiber optic "backbone" provides extended distance and additional noise immunity while the 10BaseT cabling provide[...]

CTI 2572 Technical O v erview Manual 14 The Ethernet Version 2 standard defines the packet as follows: Ethern et Destina tio n Ad dress Ethern et Sou rce Address Typ e Data CRC 6 bytes 6 bytes 2 bytes Vari able 4 bytes The type field is used to define the upper level protocol being used (e.g. TCP/IP, DEC LAT, etc.). The IEEE 802.3 specification sub[...]

CTI 2572 Technical O v erview Manual 15 As you may notice, the Ethernet II format provides the Ethernet type information in 2 bytes while the 802.3 SNAP requires 8 bytes to provides this information. Consequently, most TCP/IP installations use the Ethernet II frame format. The 802.3 SNAP format is typically used only when strict 802.3 compatibility[...]

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CTI 2572 Technical O v erview Manual 17 CHAPTER 4. NETWORK PROT OCOLS 4.1 Connectionless vs. Connection Oriented Protocols In most networking discussions you will find references to connectionless and connection- oriented services. The following analogy may help you understand the features and advantages of each. Connectionless Protocols Connection[...]

CTI 2572 Technical O v erview Manual 18 Connection-Oriented Protocols Connection-oriented protocols may be compared to a personal telephone call. Before you begin a conversation, you establish a connection by dialing a number and verifying that you are talking to the desired person. Connection-oriented network protocols work in a similar manner. Fi[...]

CTI 2572 Technical O v erview Manual 19 IPX/SPX IPX (Internet Packet eXchange) and SPX (Sequenced P acket eXchange) are proprietary protocols used by Novell Netwar e. IPX is similar to Xerox’ s Internet Da tagram Protocol. IPX provides an unreliable connectionless transmission service. Since IPX is classified as an unreliable protocol, upper leve[...]

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CTI 2572 Technical O v erview Manual 21 CHAPTER 5. TCP/IP OVERVIEW 5.1 TCP/IP Components TCP/IP consists of a hierarchy of related protocols. Upper level protocols are encapsulated in the data structure of lower level protocols. In a typical application using the 2572, the host computer application sends PLC commands via either TCP (Transmission Co[...]

CTI 2572 Technical O v erview Manual 22 5.2 Internet Protocol Internet Protocol (IP) provides a basic packet delivery service. Technically, this service is defined as unreliable, connectionless, and best-effort. Unreliable means that delivery is not guaranteed by the protocol. The packet may be lost, duplicated, delayed, or delivered out of order. [...]

CTI 2572 Technical O v erview Manual 23 A typical IP address consists of a network ID portion and a host ID portion. The distribution of the address bytes between network ID and host ID is defined by the address class. Class A uses the first byte for the network ID and the remaining three bytes for the host ID. Class B uses two bytes for the networ[...]

CTI 2572 Technical O v erview Manual 24 the datagram may actually pass through many gateways before reaching the destination network. IP has defined a comprehensive set of rules for processing datagrams. Among these specifications are the Internet Control Message Protocol (ICMP). Internet Control Message Protocol (ICMP) As described above, IP uses [...]

CTI 2572 Technical O v erview Manual 25 UDP headers are contained in IP datagrams. Data is directed to a particular process by the use of a port number. In essence, a port is a message queue for the destination application. Certain port numbers may be universally assigned and are called well known ports. Echo, Time, Nameserver , and SNMP (Simple Ne[...]

CTI 2572 Technical O v erview Manual 26 TCP will notify both application programs. Typica lly one host computer (serve r) issues a passive open to a port, making the services available. Another host computer (client) issues an active open to initiate the connection. When the application session is complete, the connection is termina ted by issuing [...]

CTI 2572 Technical O v erview Manual 27 5.6 Berkeley Sockets Although TCP/IP defines the network data structures and the rules for processing network traffic, it does not define exactly how appl ication software interfaces with TCP/IP protocols. Thi s attribute has given deve lopers the freedom to optimize software for various processor c lass, ope[...]

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CTI 2572 Technical O v erview Manual 29 CHAPTER 6. PLC COMM AND INTERF ACE 6.1 Non Intelligent Terminal Protocol As discussed in previous sections of this manual, application programs communicate with the PLC by sending messages to the 2572 encapsulated in the TCP/IP protocol. The most common message format used by SIMATIC TI505 series PLCs is the [...]

CTI 2572 Technical O v erview Manual 30 6.2 Task Codes As noted above the first word of the body of an NITP message contains a command. SIMATIC TI505 PLCs use a command structure known as task codes . Task codes are a set of numeric command codes which allow an external device to supervise and control the operation of the PLC. For example, using ta[...]