Chapter 9 Appendix-Serial interface network use and communications protocoll
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gained by the cyclic redundancy algorithm method. MODBUS RTU mode uses
hexadecimals to transmit data.
This MODBUS-I Protocol uses RTU transmission mode. The Verification Code
uses CRC-16-IBM (polynomial is X16+X15+X2+1, shield character is 0xA001)
which is gained by the cyclic redundancy algorithm method. MODBUS-I RTU
mode uses hexadecimals to transmit data.
9.3.2.1. MODBUS protocol function code and format
The flow meter protocol supports the following two-function codes of the MODBUS:
Function Code
Performance Data
0x03
Read register
0x06
Write single register
9.3.2.2. MODBUS protocol function code and format
The host sends out the read register information frame format:
Slave
Address
Operation
Function Code
First Address
Register
Register
Number
Verify Code
1 byte
1 byte
2 bytes
2 bytes
2 bytes
0x01~0xF7
0x03
0x0000~0xFFFF 0x0000~0x7D CRC(Verify)
The slave returns the data frame format:
Slave
Address
Read Operation
Function Code
Number of
Data Bytes
Data Bytes
Verify Code
1 byte
1 byte
1 byte
N*x2 byte
2 bytes
0x01~0xF7
0x03
2xN*
N*x2
CRC(Verify)
N*
＝
data register number
The range of flow meter addresses 1 to 247 (Hexadecimal: 0x01
～
0xF7 ), and can
be checked in the Menu 46. For example, decimal number "11" displayed on
