Page 3 - DOCUMENT DISCLAIMER STATEMENT
CTI 2572 Technical Overview Manual Copyright 1993, 1998 Control Technology Inc. All rights reserved. This manual is published by Control Technology Inc., 5734 Middlebrook Pike, Knoxville, TN37921. This manual contains references to brand and product names which are tradenames,trademarks, and/or regi...
Page 5 - PREFACE
CTI 2572 Technical Overview Manual i PREFACE This Technical Overview Manual provides an introduction to CTI 2572 Ethernet TCP/IPAdapter and to the networking specifications used with the module. The manual is intended forthose individuals who wish to gain a fundamental understanding of the 2572, Eth...
Page 7 - iii; TABLE OF CONTENTS
CTI 2572 Technical Overview Manual iii TABLE OF CONTENTS CHAPTER 1. INTRODUCTION.................................................................................................. 1 1.1 Description ..........................................................................................................
Page 9 - TABLE OF FIGURES
CTI 2572 Technical Overview Manual v TABLE OF FIGURES Figure 1 CTI 2572 .......................................................................................................................... 1Figure 2 Token Ring Topology...............................................................................
Page 11 - CHAPTER 1. INTRODUCTION
CTI 2572 Technical Overview Manual 1 CHAPTER 1. INTRODUCTION 1.1 Description The 2572 Ethernet TCP/IP Adapter is a single wide I/O modulewhich connects SIMATIC TI505 controllers to Ethernet networks.Using TCP/IP (Transmission Control Protocol/ Internet Protocol),other controllers or computers can ac...
Page 12 - Server Mode
CTI 2572 Technical Overview Manual 2 1.2 2572 Functions Server Mode In Server Mode, the module responds to PLC commands embedded in the TCP/IP packet. Theinitiating device (usually a computer or a 2572 operating in client mode) encapsulates the PLCcommand in the TCP/IP protocol and transmits it to t...
Page 13 - CHAPTER 2. LOCAL AREA NETWORK OVERVIEW
CTI 2572 Technical Overview Manual 3 CHAPTER 2. LOCAL AREA NETWORK OVERVIEW Local Area Networks (LANs) grew from the need to interconnect many intelligent devices in anon-proprietary manner. Today, the most widely used LAN standards are Token-Ring (IEEE802.5) and Ethernet (IEEE 802.3). Token Bus (IE...
Page 14 - Figure 2 Token Ring Topology
CTI 2572 Technical Overview Manual 4 2.2 IEEE 802.5 (Token-Ring) Token Ring (IEEE 802.5) uses a ring topology. Each station on the network has twoconnections - one to the "downstream" stationand one to the "upstream" stations. Eachstation receives network data from thedownstream stat...
Page 16 - Future Technologies
CTI 2572 Technical Overview Manual 6 The primary disadvantage of Ethernet is that the response time is not consistent under widelyvarying loads. As the network loading increases above 50% , collisions occur more frequentlyand the network response time increases. In practice, most large busy networks...
Page 19 - CHAPTER 3. ETHERNET OVERVIEW; ISO Reference Model; Layer; Synchronizes communications between applications
CTI 2572 Technical Overview Manual 9 CHAPTER 3. ETHERNET OVERVIEW 3.1 ISO Reference Model Modern network implementations separate data communication functions into layers. Each layerperforms a specific set of services and interacts with layers above and below in a well definedway. In 1984 the Intern...
Page 20 - Ethernet Topologies and Media - Physical Layer
CTI 2572 Technical Overview 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 theformal IEEE 802.3 specification is used to describe all Ethernet media. The 802.3 specificationprovides for a variety of...
Page 21 - Figure 6 10BaseT (Unshielded Twisted Pair)
CTI 2572 Technical Overview Manual 11 Although 10Base2 cabling avoids the expense of a hub, it presents a major disadvantage for largeinstallations. Because "T" connectors are used at each tap, there are two connections to the maincable for each node. Should a problem develop with the "T...
Page 22 - Figure 7 Fiber Optic Hub; Figure 8 Ethernet Bridge
CTI 2572 Technical Overview Manual 12 FOIRL (Fiber Optic) Like the 10BaseT standard, the fiber opticcabling scheme uses a hub technology. Network stations are connected to the hubvia point to point fiber optic connections. The fiber optic cable is attached to thenetwork adapter using transceiverscon...
Page 23 - Mixed Media; Figure 9 Mixed Ethernet Media
CTI 2572 Technical Overview Manual 13 Mixed Media Multiple media types may be used onthe same network. In largerinstallations it is very common fordistributed 10baseT hubs to beinterconnected via a fiber optic hub. The fiber optic "backbone" providesextended distance and additional noiseimmu...
Page 24 - The Ethernet Version 2 standard defines the packet as follows:
CTI 2572 Technical Overview Manual 14 The Ethernet Version 2 standard defines the packet as follows: EthernetDestination Address EthernetSource Address Type Data CRC 6 bytes 6 bytes 2 bytes Variable 4 bytes The type field is used to define the upper level protocol being used (e.g. TCP/IP, DEC LAT,et...
Page 25 - Ethernet Addresses
CTI 2572 Technical Overview Manual 15 As you may notice, the Ethernet II format provides the Ethernet type information in 2 byteswhile the 802.3 SNAP requires 8 bytes to provides this information. Consequently, most TCP/IPinstallations use the Ethernet II frame format. The 802.3 SNAP format is typic...
Page 27 - CHAPTER 4. NETWORK PROTOCOLS; Connectionless vs. Connection Oriented Protocols
CTI 2572 Technical Overview Manual 17 CHAPTER 4. NETWORK PROTOCOLS 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 advantage...
Page 28 - Connection-Oriented Protocols
CTI 2572 Technical Overview Manual 18 Connection-Oriented Protocols Connection-oriented protocols may be compared to a personal telephone call. Before you begina conversation, you establish a connection by dialing a number and verifying that you are talkingto the desired person. Connection-oriented ...
Page 29 - It has a proven track record for performance and reliability,
CTI 2572 Technical Overview Manual 19 IPX/SPX IPX (Internet Packet eXchange) and SPX (Sequenced Packet eXchange) are proprietaryprotocols used by Novell Netware. IPX is similar to Xerox’s Internet Datagram Protocol. IPXprovides an unreliable connectionless transmission service. Since IPX is classifi...
Page 31 - Figure 11 TCP/IP Data Encapsulation
CTI 2572 Technical Overview 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 thedata structure of lower level protocols. In a typical application using the 2572, the host computer application sen...
Page 32 - Internet Protocol; Notation; Binary
CTI 2572 Technical Overview Manual 22 5.2 Internet Protocol Internet Protocol (IP) provides a basic packet delivery service. Technically, this service isdefined as unreliable, connectionless, and best-effort. Unreliable means that delivery is notguaranteed by the protocol. The packet may be lost, du...
Page 33 - Address Class; Subnet Address Mask
CTI 2572 Technical Overview Manual 23 A typical IP address consists of a network ID portion and a host ID portion. The distribution ofthe address bytes between network ID and host ID is defined by the address class. Class A usesthe first byte for the network ID and the remaining three bytes for the ...
Page 35 - As compared to UDP, TCP adds the following functionality:; Figure 13 UDP Datagram
CTI 2572 Technical Overview Manual 25 UDP headers are contained in IPdatagrams. Data is directed to aparticular process by the use of aport number. In essence, a port is amessage queue for the destinationapplication. Certain port numbersmay be universally assigned and arecalled well known ports. Ech...
Page 36 - Reliable Data Transfer; Figure 14 TCP Segment
CTI 2572 Technical Overview Manual 26 TCP will notify both application programs. Typically one host computer (server) issues apassive open to a port, making the services available. Another host computer (client)issues an active open to initiate the connection. When the application session iscomplete...
Page 37 - Berkeley Sockets
CTI 2572 Technical Overview 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 application software interfaces with TCP/IP protocols. Thisattribute has given developers the freedom to optimize...
Page 39 - CHAPTER 6. PLC COMMAND INTERFACE; Non Intelligent Terminal Protocol; Figure 15 NITP Message Format
CTI 2572 Technical Overview Manual 29 CHAPTER 6. PLC COMMAND INTERFACE 6.1 Non Intelligent Terminal Protocol As discussed in previous sections of this manual, application programs communicate with thePLC by sending messages to the 2572 encapsulated in the TCP/IP protocol. The most commonmessage form...
