UNIT: II COMPONENTS OF CIM Two Mark Question and Answer: 1. Explain CIM. CIM is the integration of the total manufacturing enterprise through the use of integrated systems and data communications coupled with new managerial philosophies that improve organizational and personnel efficiency. 2. What are the components of CIM? 3. What is the role of CIM in manufacturing? CIM is most closely associated with functions in manufacturing engineering such a process planning and numerical control (NC) part programming. 4. What are the important applications of CIM in manufacturing control? ♦ the applications of computer process control are pervasive today in automated production systems. ♦ Quality control includes a variety of approaches to ensure the highest possible quality levels in the manufactured product. ♦ Shop floor control refers to production management techniques. 5. What is the major communication used in manufacturing industry? The major communication used in manufacturing industry 1. Telephones, including cellular systems 2. Facsimile terminals (or) Fax machines 3. Satellite dish and video conferencing 4. Personal computers (PCs) 6. What is MAP? Manufacturing Automation Protocol (MAP) is a specialized LAN designed for a factory environment. It is hardware cum-software implement able set of rules that facilitate information transfer among networked computers and computer-based equipment. 7. What are the approaches of physical distributions? • Customer service: What level of customer service should be provided? • Transportation: How will the products be shipped? • Warehousing: Where will the goods be located? How many warehouses should be utilized? • Order processing: How should the order is handled? • Inventory control: How much inventory should be maintained at each location? • Protective packing and materials handling: How can efficient methods be developed for handling goods in the factory, warehouse, and transport terminals? 8. What are two types of transmission mode? There are three transmission modes available. They arc i) Simplex ii) Half-duplex iii) Duplex. They can be applied to both analog and digital channels. 9. What is modulation? The process of varying amplitude or frequency or phase of the carrier signal in accordance with the instantaneous value of the information signal is known as modulation. 10. What are the reasons for using LAN? 1. LAN allows for decentralization of various data processing functions. 2 LAN allows departments to share hardware. 3. LAN allows for the electronic transfer of text. 4. LAN allows for communication between organizations. 5. LAN allows information to be shared. 11. Define topology and explain its classification. The pattern of interconnection of nodes in a network is called topology. Topology can also be defined as the geometric arrangement of workstations and the links among them. The types of LAN topology are i) Bus topology ii) Ring topology iii) Star topology iv) Mesh topology 12. List out the layers of OSI model. Seven layers in OSI model i) Physical layer ii) Data link layer iii) Network layer iv) Transport layer v) Session layer vi) Presentation layer vii) Application layer 13. List the application protocols of TCP/IP. A number of application protocols and user applications have been developed based on TCP/IP. These include Telnet, FTP, Network File System (NFS), Simple Mail Transfer Protocol (SMTP), and Simplified Network Management Protocol (SNMP). 14. What is Hierarchical Data Model? The hierarchical data model is similar to the network data model except that the relationships among the records are represented in the form of tree structure. 15. What is Data Associations? A link describes an association between two records. The following are the different types of data associations used in DBMS in manufacturing scenario. 1. One-to-one association 2. One-to-many association 3. Many-to-many association 1. Explain in detail about the Computer Network Reference Model COMPUTER NETWORK REFERENCE MODEL A data communication network requires high degree of compatibility and interoperability among network elements, particularly with respect to its physical and logical interfaces and controls. The International Organization for Standardization (ISO) established a committee to develop a standard architecture to achieve the long-term goal of Open Systems Interconnection (OSI). The term OSI denotes the standards for the exchange of information among systems “open” to one another by virtue of incorporating the ISO standards. Examples of application processes that may wish to communicate in an open way are: A process (program) executing in a computer and accessing a remote file system A process in a supervisory computer controlling a distributed community of computer-based instruments or robot controllers associated with a process or automated manufacturing plant A process in an instrument or robot controller receiving commands and returning results to a supervisory system A process in an office workstation (computer) accessing an electronic mail (e-mail) service OSI is concerned with the exchange of information between such processed. The aim is to enable application processes to cooperate in carrying out a particular (distributed) information-processing task irrespective of the computers on which they are running. For this purpose, ISO has specified an OSI reference model that segments the communications functions into seven layers. Each layer is assigned a related subset of communications functions, which are implemented in data terminal equipment (DTEs) that communicate with other DTEs. Each layer relies on the next lower layer to perform more primitive functions and in turn provides services to support the next higher layer. The layers are defined so that changes in one layer do not affect other layers. ISO reference model for OSI There are seven layers in the OSI model: 1. Physical Layer – Consists of the hardware that drives the network and circuits. It specifies the type of cable or transmission media that is used – Twisted-Pair, Coaxial, Fiber-optic, radio waves. 2. Data link layer – Handles the task of transferring information across the physical link by sending blocks of data (frames) with necessary synchronisation, error control, and flow control functions – CSMA/CD (Ethernet) , Token Bus (Token Ring) 3. Network Layer – Decides which outgoing line will be used to send the message to a node. Because it knows about the physical connections and paths between the transport entities in a session, it relives the transport layer of the need to know anything about the underlying network technologies used to connect end systems. 4. Transport Layer – Provides transparent transfer of packets (data) to and from the session layer without disruption. Has three major functions: establishing a connection of the right type and quality (speed), initiating data transfer and managing the data to be sent, and releasing the connection. 5. Session Layer – Control communication between applications by establishing, managing, and terminating virtual connections between cooperating applications. 6. Presentation Layer – Performs certain decoding and conversion operations on data to match the device and network requirements. Responsible for making the application processes independent of differences in data representation. 7. Application Layer – Provides the user interface to the networking system. Therefore, in most cases user writes the application layer. The services provided by this layer include terminal emulation, file transfer, electronic mail, and distributed database managers. A number of protocols have been developed based on the OSI reference model. The most known one is TCP/IP, SNA, DECNET, MAP/MOP/MMS (Manufacturing message service). 2.Explain the various types of computer networks TYPES OF COMPUTER NETWORKS Depending on the geographic area covered computer networks are divided into following categories: • Local Area Networks (LANs) - Used to interconnect computers within the same building or organisation. A LAN typically operates at speeds ranging from 10 Mbps to 100 Mbps, connecting several hundred devices over a distance of up to 5 to 10 km. Metropolitan Area Networks (MANs) - MANs are large LANs that cover a large city or suburb. Used to interconnect LANs within a metropolitan area. A typical MAN operates at a speed of 1,5 to 150 Mbps. • Wide Area Networks (WANs) - Use common carrier facilities over long distances and are used to connect sites and facilities over the countries. Usually the speed between the cities can vary from 1.5 Mbps to 2.4 Gbps. In a WAN, the cost of transmission is very high, and the network is usually owned and operated by a public network. • Global Area Networks (GAN) – these are networks connections between countries around the globe. A GAN’s speed ranges from 1.5Mbps to 100Gbps and its reach is several thousands of kilometers 3. Explain the various network topology Bus Topology One of the most used network layout in which single cable, usually coaxial, is routed through locations where connection of machines, computers or devices is made, and is terminated on both sides. This Advantages: low initial price, less cable required. Disadvantage: All devices connected share the same cable. On any problem, or short circuit on cable, all of the devices are disconnected. Star Network Topology Star Network Topology is achieved using hubs interconnected with Twisted-Pair Cable. Hub is device in which there is internal bus network and all of the devices are connected directly to this bus. Advantages: On case of failure on cable only the device which is connected cannot connect to the network. Every device uses its own cable. Disadvantages: More cable required in comparison to bus topology, Additional device (hub) is required. Number of devices that can be connected is limited to number of outputs located on the hub. Ring Topology With a ring topology, the network cable passes from one device to another until all of the devices are interconnected in the form of a loop or ring. An advantage of the ring topology is that the number of slots in any device does not limit the number of devices connected to the network. Tree Topology Formed in a hierarchical way by using hubs. This topology is combination of bus and star topology. An advantage of the tree topology is that it offers very flexible layouts. 4. Explain the medium access control methods in CIM? MEDIUM ACCESS CONTROL METHODS In order computers connected to the network communicated with each other in proper way, medium access control methods (or protocols) are established. These methods provide control techniques for computers to access to network. Most common is CSMA/CD (Carrier Sensed Multiple-Access with Collision Detection). Used both in Bus and Star topologies. Also known as Ethernet. Usually the speed is up to 10Mbps, but there is increasing of collisions with increasing speed, so the practical value is much less than 10Mbps. Token Ring is another medium access control method on which the collision problem is completely solved. This is accomplished by having a token at the station to authorise transmission. A token is a packet that is used to send and receive messages. Token Ring is usually used on ring topology. Another common type of medium access control method widely used in many manufacturing automation protocol environments is Token Bus. It is very similar to Token Ring, as both use token passing for medium access control. The main difference is that the token bus operates on a bus instead of a ring topology. SIGNALING METHOD Data in a network are propagated from one point to another by means of signals. The signals are therefore the electromagnetic representation of transmitted data. Data or signals converters convert the data to signals for transmission on the sending end and back to data at the receiving end. A modem is a typical example of converter. Depending on signaling method coaxial cable LANs can be divided into various categories, including baseband, broadband and carrierband. • Baseband – all the available bandwith is used to derive a single high bit rate (10 Mbps or higher) transmission path (channel). Impressing data directly to communication wire. Ethernet, Token Ring are typical examples • Broadband – all the available bandwith is divided to derive a number of lower bandwith subchannels (and hence transmission paths) on one cable. It is getting more important now, since changing user needs and demands. The broadband protocols are going to replace the current standards of Ethernet and Token Ring. Now most of the world uses Broadband signaling (SONET, ATM, Frame Relay, ISDN, B-ISDN) in MANs and WANs. INTERNET The technological progress in the communication networks is continuously going up. The main cause of this is continuously increased of amount of the information and data exchanged between people either inside organisations or worldwide. INTERNET is the global highway where all of this information, technology and people meet. TCP/IP The transmission control protocol/Internet protocol (TCP/IP) was developed by the Defence Advanced Research Projects Agency (DARPA) in the early 1970s to interconnect computers in the Advanced Research Projects Agency Network (ARPANET). The TCP/IP suite now consists of several major protocols, such as Internet Protocol (IP), transmission control protocol (TCP), Telnet, File Transfer Protocol (FTP), Simple Mail Transfer Protocol (SMTP), HyperText Transfer Protocol (HTTP) etc. TCP/IP application protocols • TELNET – Enables a user at a terminal on one machine to communicate interactively with an application or user on a remote machine, as if the user terminal were connected directly. • FTP (file transfer protocol) – Enables a user at a terminal or user application to access and interact with a remote file system. • SMTP (simple mail transfer protocol) – Provides a networkwide mail transfer service between the mail systems associated with different machines. • SNMP (simple network management protocol) - Enables a user (for example, network manager), to gather performance data or to control the operation of a network element via the network itself. • HTTP (hypertext Transfer Protocol) - one of the most popular one. World Wide Web service is given with the means of this protocol. 5. Explain the concept of MAP and TOP MANUFACTURING Parallel with increasing needs for faster communications the needs of large data storage capacity and fast computers (supercomputers) is increasing also. Now typical manufacturing environment, called also as CAD/CAM/CAE environment is composed of supercomputers, centralized data storage units, CNC controlled machine centers, robots etc., all connected on the same network. On this networks either TCP/IP or specially designed manufacturing protocols like, MAP or TOP, are used. MAP An initiative by General Motors of The United States has resulted in the selection of a set of protocols, all based on ISO standards, to achieve open system interconnection within an automated manufacturing plant. The resulting protocols are knows as manufacturing automation protocols (MAPs). As we can see, MAP is based on a factory-wide, backbone cable distribution network. The cable is coaxial and operates at 10Mbps. Because of the wide range of communication requirements within a factory, the broadband mode of working has been selected. The Media Access Control Method is Token Bus. TOP In a similar way, an initiative by the Boeing Corporation (USA) has resulted in the selection of a set of ISO standards to achieve open system interconnection in a technical and office environment. The selected protocols are known as technical and office protocols (TOPs). The transmission medium used with a TOP network is also coaxial cable operating at 10Mbps, using CSMA/CD Media Access control method in baseband mode. In general, the communication requirements in such environments are limited to voice (which is normally already provided by the existing telephone system) and data, the latter being primarily concerned with communications between a distributed community of advanced workstations. 6. Explain CASA /SME model in Computer Integrated Manufacturing Computer Integrated Manufacturing (CIM) technology concerns the developing field of automated manufacturing and materials handling. The use of computers applied to design, machining and manufacturing of products, as well as in quality and process control, is emphasized. CIM is defined differently by different users, and can be implemented in varying an increasing degree of complexity. For many companies, improving shop-floor communications is the primary goal. Others extend the degree of integration to encompass communication between engineering and manufacturing functions. The ultimate benefit of CIM is the improvement of communication and control of information flow to all aspects of an enterprise. Integrating information and organizations will decrease the logistical size of a company, making it appear to be small again-at least from the management, administration, and information-sharing viewpoints. The goal of CIM is to provide the computer applications and communications needed to bring about the integration (with matching organization changes) that will allow a company to take advantage of these new capabilities. CIM the Enterprise Wide Solution In any manufacturing enterprise there is a unique set of business processes that is performed in order to design...produce...and market the enterprise’s products.. But no matter how unique an enterprise or its set of processes, every enterprise shares the same set of high- level objectives. This is to: • Manage manufacturing finance and accounting • Develop enterprise directives and financial plans • Develop and design products and manufacturing processes • Conduct manufacturing operations • Manage external demands Computer Integrated Manufacturing harnesses information system technology to integrate these manufacturing and business objectives. When implemented properly, CIM can deliver increased productivity, cost-efficiency and responsiveness throughout the enterprise. CIM accomplishes this by addressing each of the major functional areas of the manufacturing enterprise: • Marketing • Engineering and Research. • Production Planning • Plant Operations • Physical Distribution • Business Management Integrating these functions and their resources requires the ability to share and exchange information about the many events that occur during the various phases of production; manufacturing systems must be able to communicate with the other information systems throughout the enterprise. There must also be the means to capture data close to its source, and then integrate this data at a division or corporate level, as well as with external suppliers, sub-contractors and even customer To meet this need, the CIM environment requires a dynamic network of distributed functions. These functions may reside on independent system platforms and require data from various sources. Some may be general- purpose platforms, while others are tailored to specific environments. But the result is an environment that encompasses the total information requirements of the enterprise—from developing its business plan to ship ping its products. With this enterprise-wide emphasis, CIM can deliver its benefits to all types of manufacturing operations, from plants that operate one shift per day to processes that must flow continuously...from unit fabrication and assembly to yielded lots with by-products and co-products. These benefits can also be realized in those enter prices where flexible manufacturing systems are being used to produce more diversified products over shorter runs, as well as by integrating the management of the CIM enterprise with automated office systems. Cim Benefits: By creating a more efficient, more comprehensive information system environment, CIM supports management efforts to meet the challenges of competing effectively in today’s world markets. The CIM advantage translates into a wide range of benefits. When Computer Integrated Manufacturing is implemented in an enterprise, the benefits can be felt far beyond the plant floor and its manufacturing process. They extend into each of the functional areas of the manufacturing enterprise. In Marketing, CIM helps manage customer satisfaction by allowing electronic order entry from customers... through faster response to customer inquiries and changes...and with more accurate sales projections. In Engineering and Research, CIM benefits include quicker design, development, prototyping and testing... faster access to current and historical product information...and a method for paperless release of products, processes and engineering changes to manufacturing. In Production Planning CIM offers more accurate, realistic production scheduling...while it requires less expediting, canceling and rescheduling of production and purchase orders. Within Plant Operations, CIM provides the means to assist the manufacturing operations in controlling processes, optimizing inventory, improving yields, managing changes to products and processes, reducing scrap and rework. CIM also helps utilize people and equipment more effectively.. .and reduces crisis production demands as well as lead times and product costs. In Physical Distribution, where external demands are satisfied with products shipped to the customer, CIM helps plan requirements...manage the flow of products .improve efficiency of shipping, vehicle and service scheduling...allocate supply to distribution centers...and expedite processing of returned goods. For Business Management activities such as managing manufacturing finance and accounting, and developing enterprise directives and financial plans. CIM offers better product’ cost tracking...more accuracy in financial projections...and improved cash flow. For the enterprise as a whole, these advantages add up to faster release of new products.. .shorter delivery times.. .optimized finished goods inventory...shorter production planning and development cycles.. .reduced production lead times... improved product quality, reliability and serviceability...increased responsiveness and greater competitiveness. In effect, CIM replaces an enterprise’s short-term tactical improvements with a long-term strategic solution. Of course, the advantages of CIM aren’t just contained within the four walls of your enterprise. It can also deliver real productivity gains to those outside your enterprise. For example, suppliers will be able to plan production, schedule deliveries and track shipments more efficiently. And your customers will benefit from shorter order-to-delivery times; ontime deliveries; and less expensive higher-quality products. As you can see, the integration and productivity gains made possible by CIM are key to maintaining a competitive edge in today’s manufacturing environment. Transmission modes: The term Transmission Mode defines the direction of the flow of information between two communication devices i.e. it tells the direction of signal flow between the two devices. There are three ways or modes of data transmission: Simplex, Half duplex (HDX), Full duplex (FDX) Transmission Mode Simplex: In Communication Networks, Communication can take place in one direction connected to such a circuit are either a send only or receive only device. There is no mechanism for information to be transmitted back to the sender. Communication is unidirectional. TV broadcasting is an example. Simplex transmission generally involves dedicated circuits. Simplex circuits are analogous to escalators, doorbells, fire alarms and security systems: Examples of Simplex mode: ACommunication between a computer and a keyboard involves simplex duplex transmission. A television broadcast is an example of simplex duplex transmission. 2. Another example of simplex transmission is loudspeaker system. An announcer speaks into a microphone and his/her voice is sent through an amplifier and then to all the speakers. 3. Many fire alarm systems work the same way. Simple Transmission Half Duplex: A half duplex system can transmit data in both directions, but only in one direction at a time that mean half duplex modes support two-way traffic but in only one direction at a time. The interactive transmission of data within a time sharing system may be best suited to half-duplex lines. Both the connected devices can transmit and receive but not simultaneously. When one device is sending the other can only receive and vice-versa. Data is transmitted in one direction at.a time, for example. a walkie-talkie. This is generally used for relatively low-speed transmission, usually involving two-wire, analog circuits. Due to switching of communication direction, data transmission in this mode requires more time and processes than under full duplex mode. Examples of half duplex application include line printers, polling of buffers, and modem commuriications (many modems can support full duplex also). Half Duplex Mode Example of half duplex mode: A walkie-talkie operates in half duplex mode. It can only send or receive a transmission at any given time. It cannot do both at the same time. As shown in fig. computer A sends information to computer B. At the end of transmission, computer B sends information to computer A. Computer A cannot send any information to computer B, while computer B is transmitting data. Full Duplex: A full duplex system can transmit data simultaneously in both directions on transmission path. Full-duplex method is used to transmit the data over a serial communication link. Two wires needed to send data over a serial communication link layer. Full-duplex transmission, the channel capacity is shared by both communicating devices at all times. Both the connected devices can transmit and receive at the same time. Therefore it represents truly bi-directional system. The link may contain two separate transmission paths one for sending and another for receiving.
Posted on: Sun, 17 Aug 2014 16:01:32 +0000
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