Read-write memory read instruction(03)

The length of total register requested by a single reading command must be less than or equal to 20 registers. Instructions longer than this will be ignored.

Instruction example

Format of command (03) from master

Byte#	1	2	3	4	5	6	7	8
Node ID	Slave Address	Function Code	Address of first reading register	Address of first reading register	Quantity of registers to be read	Quantity of registers to be read	CRC	CRC
Example 01~FF	01	03	00	00	00	03	05	CB

Description of master command

The example will read A01 pipe diameter options and A02 Scale Factor.

slave address: 01(address of this flowmeter)

function code: 03(read instruction)

Address of first reading register: 0000(Address of first register to read)

Quantity of registers to be read: 0003 (need to read 2 registers from 0000)

CRC: 05 CB (Calculating error correcting code according to CRC algorithm)

Format of flowmeter response(03)

Byte#	1	2	3	4	5	6	7	8	9	10	11
Node ID	Slave Address	Function Code	Amount of response Byte	Data Byte #1	Data Byte #2	Data Byte #3	Data Byte #4	Data Byte #5	Data Byte #6	CRC	CRC
Example 01~FF	01	03	06	00	00	3F	80	00	00	2C	89

Description of flowmeter response example

slave address: 01(address of this flowmeter)

function code: 03(read instruction)

Amount of response Byte: 06 (3 register=6byte)

Data Byte:

• 00 00(Current pipe diameter is 1inch PVC)

• 3F 80 00 00(Current Scale Factor is 1.0)

CRC: 2C 89 (Calculating error correcting code according to CRC algorithm)