Modicon M251 Plc Page 20 Communication bus

20 Presentation Modicon M251 logic controllers Industrial Ethernet network Description of Ethernet services Network Global Variable List (NGVL) The NGVL protocol allows a controller to share data with other controllers on a local Ethernet network (LAN) or subscribe to data published by other controllers that support the NGVL protocol and thus allowing, for example synchronization between control platforms. I/O Scanning (Industrial Ethernet Manager) The Industrial Ethernet Manager service is used to manage the exchange of remote I/O states on the Ethernet network after a simple configuration operation, with no need for special programming. I/O scanning is performed transparently by means of read/write requests in accordance with the Modbus TCP or EtherNet/IP protocol, this is called Scanner Manager on Modbus TCP or Scanner Manager on EtherNet/IP. Slave Modbus TCP This function can be used to create a dedicated I/O table in the controller, which can be accessed via the Modbus TCP protocol and by a controller with the Modbus TCP I/O Scanner function. Fast Device Replacement (FDR) This service uses standard address management technologies (BOOTP, DHCP) and the TFTP (Trivial File Transfer Protocol) file management service, in order to simplify maintenance of Ethernet products. The FDR service is used to replace a device with a new one; the device is detected, reconfigured and automatically rebooted by the system. Access to files via FTP (File Transfer Protocol) This service provides access to the controller files from, for example, a PC (FTP client) and is used to exchange files such as application programs, data, etc. This service can be accessed even if the controller has no application program in its memory. Dynamic Host Configuration Protocol (DHCP) This protocol can be used to assign an address to a controller (client DHCP/ BOOTP) automatically. This address can be: v ixed and determined either in the SoMachine software or included in a post- configuration file v assigned by a controller with the DHCP server or BOOTP server function (such as the TM251MESE logic controller) SNMP (Simple Network Management Protocol) From a network management station, the SNMP protocol is used to monitor and control the Ethernet architecture components, meaning problems are diagnosed quickly. The SNMP protocol is used to access configuration and management objects that are contained in the device MIBs (Management Information Bases). Modicon M241 and M251 controllers support the MIB 2 Standard SNMP network management interface. This interface accesses a first level of network management; it enables the manager to identify the devices making up the architecture and retrieve general information about configuration and operation of the Ethernet Modbus TCP interfaces. IP address filter (Whitelisting) IP addresses that are authorized to access the controller can be loaded in the controller from either an SD card or an FTP client. Locking communication protocols Not only SoMachine, NetManage (1) , SNMP communication protocols but also Modbus, WEB and FTP servers can be locked individually in the SoMachine software. EtherNet/IP target This function can be used to create a dedicated I/O table in the controller, that can be accessed via the EtherNet/IP protocol and by a controller with the EtherNet/IP originator function. EtherNet/IP target acts in the same way for EtherNet/IP as a Modbus TCP slave. EtherNet/IP originator Controllers with this function trigger exchanges with devices featuring the Ethernet/ IP target function. EtherNet/IP originator acts in the same way for EtherNet/IP as a Modbus TCP master. (1) The NetManage function can automatically detect which controllers are present on the network. It also offers the option of straightforward connection to any controller present on the network in order to identify it physically by means of a visual or audible message and modify its parameters or manage the resident application. Ethernet TCP Device input words/output words Write Read Modicon TM251MESE controller with Industrial Ethernet Manager service Devices with Modbus TCP messaging in server mode or EtherNet/IP target messaging I/O scanning (Industrial Ethernet Manager)

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