YASKAWA VIPA System MICRO M13-CCF0000 Manual

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YASKAWA VIPA System MICRO M13-CCF0000 Manual Manual pdf 142 page image

The session layer is also called the communication control layer. It relieves the communi-cation between service deliverer and the requestor by establishing and holding the con-nection if the transport system has a short time fail out. At this layer, logical users maycommunicate via several connections at the same time. If the transport system fails, anew connection is established if needed. Additionally this layer provides methods for con-trol and synchronization tasks.This layer manages the presentation of the messages, when different network systemsare using different representations of data. Layer 6 converts the data into a format that isacceptable for both communication partners. Here compression/decompression andencrypting/decrypting tasks are processed. This layer is also called interpreter. A typicaluse of this layer is the terminal emulation.The application layer is the link between the user application and the network. The tasksof the application layer include the network services like file, print, message, data baseand application services as well as the according rules. This layer is composed from aseries of protocols that are permanently expanded following the increasing needs of theuser.6.3 Basics - TermsA network res. LAN (Local Area Network) provides a link between different stations thatenables them to communicate with each other. Network stations consist of PCs, IPCs,TCP/IP adapters, etc. Network stations are separated by a minimum distance and con-nected by means of a network cable. The combination of network stations and the net-work cable represent a complete segment. All the segments of a network form theEthernet (physics of a network).In the early days of networking the Triaxial- (yellow cable) or thin Ethernet cable (Cheap-ernet) was used as communication medium. This has been superseded by the twisted-pair network cable due to its immunity to interference. The CPU has a twisted-pair con-nector. The twisted-pair cable consists of 8 cores that are twisted together in pairs. Due tothese twists this system is provides an increased level of immunity to electrical interfer-ence. For linking please use twisted pair cable which at least corresponds to the category5. Where the coaxial Ethernet networks are based on a bus topology the twisted-pair net-work is based on a point-to-point scheme. The network that may be established bymeans of this cable has a star topology. Every station is connected to the star coupler(hub/switch) by means of a separate cable. The hub/switch provides the interface to theEthernet.The hub is the central element that is required to implement a twisted-pair Ethernet net-work. It is the job of the hub to regenerate and to amplify the signals in both directions. Atthe same time it must have the facility to detect and process segment wide collisions andto relay this information. The hub is not accessible by means of a separate networkaddress since it is not visible to the stations on the network. A hub has provisions to inter-face to Ethernet or to another hub res. switch.A switch also is a central element for realizing Ethernet on Twisted Pair. Several stationsres. hubs are connected via a switch. Afterwards they are able to communicate with eachother via the switch without interfering the network. An intelligent hardware analyses theincoming telegrams of every port of the switch and passes them collision free on to thedestination stations of the switch. A switch optimizes the bandwidth in every connectedsegment of a network. Switches enable exclusive connections between the segments ofa network changing at request.Layer 5 - Session layerLayer 6 - PresentationlayerLayer 7 - Application layerNetwork (LAN)Twisted PairHub (repeater)SwitchVIPA System MICRODeployment PG/OP communication - productiveBasics - TermsHB400 | CPU | M13-CCF0000 | en | 16-47142