Supported transmission modes:• Modbus RTU• Modbus ASCIITable 2.4.4-1 The function codes supported by Modbus OPC ServerMemory areaDescriptionFunction code00001 - 09999Read coil status0110001 - 19999Read input status0240001 - 49999Read holding register0330001 - 39999Read input registers0400001 - 09999Force single coil0540001 - 49999Write single register0640001 - 49999Write multiple registers1660001 - 65535Write General Reference21The following data formats are supported:• Bit, one coil, or input status• Word, one register in IED's memory. The data is used in an unsigned form• Integer, one register in IED's memory. The MSB bit is used as a sign bit• Long MSW last, signed 32-bit object, which needs two registers from IED's memoryin lsw-msw order• Long MSW first, signed 32-bit object which needs two registers from IED's memoryin msw-lsw order.• Float MSW last, floating point type which needs two input registers from IED'smemory in lsw-msw order• Float MSW first, floating point type which needs two input registers from IED'smemory in msw-lsw order.External OPC Server features2.4.5.OPC Data Access is used for continuous, real-time data communication betweenPLC/DCS systems and COM600 communicating real-time data from data acquisitiondevices such as PLCs to display and interface devices like Web Human-Machine Inter-faces (WebHMI). OPC DA is also used for inter-process communication in COM600.SNMP features2.4.6.The Simple Network Management Protocol (SNMP) is used to manage network con-nectivity of substation devices in the substation LAN network.The SNMP OPC Server is intended for providing methods for OPC clients to monitornetwork-attached devices.221MRS758690COM600 series 5.0Master Protocols (Ethernet) and Applications Technical Refer-ence Manual
