Communication (In Englischer Sprache); Physical Layer; Communication Protokoll - Riedconn Rc-72 Bedienungsanleitung

6. Communication

6.1 Physical layer

1) RS485 communication interface, asynchronous half-duplex mode;
2) Communication speed 2400 ~ 9600bps can be set, the factory default is 9600 bps;
3) Byte transfer format (N81, N82, E81, O81): 1 start bit, 8 data bits, (1 parity bit), 1/2 stop bit.
6.2 Communication protocol
The instrument supports the standard Modbus-RTU communication protocol.
The structure of the data frame: the message format.
address code
1 byte
Address code: is the beginning of the frame, consisting of one byte (8-bit binary code),
decimal 0 to 255, only 1~247 is used in our system, other addresses are reserved. These bits
indicate the address of the user-specified terminal device that will receive the host data from it.
The address of each terminal device must be unique, and only the terminal to which it is
addressed will respond to the corresponding query. When the terminal sends back a response,
the slave address data in the response tells the host which terminal is communicating with it.
Function code: Specify what function the terminal to be addressed performs. The
following table lists the function codes supported by the meter and their meaning and function.
Function code
0x03/0x04
Data code: Contains the data required by the terminal to perform a specific function or the
data collected by the terminal in response to a query. The contents of these data may be numeric
values, reference addresses, or set values. For example, the function code tells the terminal to
read a register, the data field needs to indicate which register to start and how many data to read,
and the slave data code returns the data length and corresponding data.
Check Code: The Error Check (CRC16) field occupies two bytes and contains a 16-bit
binary value. The CRC value is calculated by the transmitting device and then appended to the
data frame. The receiving device recalculates the CRC value when receiving the data, and then
Wir behalten uns das Recht vor, die technischen Merkmale ohne Benachrichtigung zu ändern.
function code
1 byte
0x10
www.stromverteiler24.de
Data code Check code
N byte
meaning
Read data register value
Write set register instruction
2 byte
V1.0
- 26 -