Eaton EU5C-SWD-EIP-MODTCP Manual

Also see for EU5C-SWD-EIP-MODTCP: Application Instruction leaflet Instruction leaflet Instruction leaflet Instruction leaflet

Contents

7 Modbus/TCP – SmartWire-DT implementation6.2 Manufacturer-specific object classes72 SmartWire-DT Gateway EU5C-SWD-EIP-MODTCP 08/17 MN120003Z EN www.eaton.com7 Modbus/TCP – SmartWire-DT implementationThe Modbus-TCP communication system is based on the TCP/IP protocolbeing used. All data and parameters are entered into the TCP/IP frame's use-ful information data range. This data is integrated into a special MBAP framethat ensures that the data will be interpreted unambiguously. "MBAP" standsfor ModBus Application Protocol. Special function codes are used to accessthe data (function codes 1 - 255).Communications between Modbus modules are based on the client/serverprinciple. The client, e.g., the PLC, uses function codes to transmit a requestto the server, e.g., the EU5C-SWD-EIP-MODTCP gateway. The serverresponds to the request and returns the requested data to the client. If anerror occurs during the communication request, e.g., because a request isnot permitted, the client will receive an error message.Data model and Modbus registersIn principle, Modbus differentiates between bit data and word data. Each ofthese is further subdivided into two available types:These data structures are provided from the Modbus server side. The scopeof the data access functions and the maximum number of data objects areboth independent of the specific implementation being used.In the case of Modbus, there are multiple addressing methods that can beused to access the data in the PLC. Their use depends on the selected PLCand the corresponding programming system. For example, when using the5-digit addressing method, the PLC will work with an offset of 40001 and theentire data storage area will be offset by this number.All references in this documentation are specified as hexadecimal values.Data Object Data type Access maximum numberInput Status BIT Read 65536Coil Status BIT Read / Write 65536Input Register Word Read 65536Holding register Word Read / Write 65536￫ The EU5C-SWD-EIP-MODTCP gateway only supports access toinput and output registers.