ICP DAS USA PETL Series User Manual

Also see for PETL-7060: Quick start guide Quick start guide User manual

ICP DAS USA PETL Series User Manual Manual pdf 85 page image

Ethernet I/O ModulesICP DAS CO., LTD. PETL/tET/tPET DIO Series User Manual, Ver. 2.2, Aug. 2017, Page: 85 The Leading 6 bytes of a Modbus/TCP Protocol QueryByte 00 Byte 01 Byte 02 Byte 03 Byte 04 Byte 05Transaction identifier Protocol identifier Length Field(upper byte )Length Field(lower byte)Transaction identifier = Assigned by the Modbus/TCP master (client)Protocol identifier = 0Length field (upper byte) = 0 (since all messages are smaller than 256)Length field (lower byte) = The number of following RTU data bytes RTU Data StructureByte 06 Byte 07 Bytes 08-09 Bytes 10-11Net ID(Station Number) Function CodeData FieldReference Number(Address Mapping) Number of Points1. Net ID specifies the address of the receiver (Modbus/TCP slave).2. Function Code specifies the message type.3. Data Field is the data block.