Modbus 簡介 - files.bacnet.webnode.tw

1 Modbus (Eric) ModbusModbusModbusModbus Modbus Modicon ( Schneider ) 1978 Modbus Modbus PLC 1998 Schneider TCP/IP ModbusTCP Modbus Modbus Modbus Modbus Modbus RS-232 RS-422 RS-485 RS-485 Modbus Modbus Modbus Modbus Modbus (Master)/ (Slave) ; Slave 1 247 Slave Slave Master ; 0 ; RTU ASCII Modbus RTU Modbus RTU Modbus RTU Modbus RTU 16 Byte CRC ASCII CRC LRC 2 bytes0 ~252 bytes1 byte1 byteCRC Slave Modbus ASCII Modbus ASCII Modbus ASCII Modbus ASCII : CR -LF ASCII LRC RTU 2 bytes CR LF 2 bytes0 ~ 2*252 bytes2 bytes2 byte1 byte.

2 LRC Slave Preset Multiple Regs16 Force Multiple Coils15 Preset Single Register06 Force Single Coil05 Read Input Registers04 Read Holding Registers03 Read Input Status02 Read Coil Status01 Modbus RTU Modbus RTU Modbus RTU Modbus RTU 76H 87H03H00H6BH00H03H11 HCRC Slave 20H 18H02H 2BH 00H 00H 00H 64H06H03H11 HCRC Byte Slave Slave RTU Response Master RTU Query Modbus RTU Modbus RTU Modbus RTU Modbus RTU 76H 87H03H00H6BH00H03H11 HCRC Slave C1H 34H02H83H11 HCRC Slave Slave RTU Response Master RTU Query (Exception Codes)(Exception Codes)(Exception Codes)(Exception Codes)Slave SLAVE DEVICE BUSY06 ( )ACKNOWLEDGE 05 Slave SLAVE DEVICE FAILURE04 ILLEGAL DATA VALUE 03 LLEGAL DATA ADDRESS02 ILLEGAL FUNCTION01 Modbus TCP IANA (Internet Assigned Numbers Authority.)

3 Modbus TCP / UDP 502 Modbus TCP MBAP MBAP Modbus Application Protocol MBAP Modbus TCP/IP PDU PDU MBAP MBAP MBAP MBAP Client Slave 1 Byte Unit IdentifierServer Client 2 Bytes Length ( 0)Client ( 0) Modbus 02 Bytes Protocol Identifier Client 2 Bytes Transaction IdentifierServer Client Modbus Modbus Modbus Modbus (((( BACnet)BACnet)BACnet)BACnet) - + - Slave !! :Modicon Modbus Protocol Reference Guide PI MBUS 300 Rev.

4 JMODBUS MESSAGING ON TCP/IP IMPLEMENTATION GUIDE Rev 8 May02