Serial Transmission Modes (Rtu); Ethernet Transmission Modes - Beko METPOINT BDL Compact Installation And Operating

METPOINT ® BDL Compact
3.3.1 Serial transmission modes (RTU)
The BDL Compact Modbus mode support only one serial transmission modes; the RTU mode. The
transmission mode defines the bit contents of message fields transmitted serially on the line. It determines
how information is packed into the message fields and decoded.The transmission mode and serial port
parameters must be the same for all devices on a Modbus serial line.
RTU mode Modbus Application Data Unit (ADU) frame is shown below, and is valid for both requests and
responses.
Client Address
1 byte
Table 1
Further details of the Modbus protocol can be found in Reference 1 and 2.
3.3.2 Ethernet transmission modes
The BDL Compact Modbus mode supports the Modbus/TCP only
The transmission mode defines the bit contents of message fields transmitted serially on the line. It
determines how information is packed into the message fields and decoded.
The transmission mode and serial port parameters must be the same for all devices on a Modbus serial line.
Modbus/TCP mode Modbus Application Data Unit (ADU) frame is shown below, and is valid for both
requests and responses
Modbus/TCP MBAP Header
Transaction Protocol
Id
2 byte
Table 2
6 | 32
Function code
1 byte
Length
Id
2 byte 2 byte
Data
0 ... 252 byte(s)
PDU
Unit Id Function
Code
1 byte 1 byte
Daisychain setup
CRC
2 bytes
Data
0 ... 252 byte (s)