Read-only memory read instruction(04) and memory lists

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

CommentShare feedback on the editorFormat of command (04) from masterCommentShare feedback on the editor

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	04	00	00	00	02	71	CB

Description of master command

The example will read instantaneous flow volume.

slave address: 01(address of this flowmeter)

function code: 04(read instruction)

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

Quantity of registers to be read: 0002 (need to read 2 registers from 0000)

CRC: 71 CB(Calculating error correcting code according to CRC algorithm)

Format of flowmeter response(04)

CommentShare feedback on the editor

Byte#	1	2	3	4	5	6	7	8	9
Node ID	Slave Address	Function Code	Amount of response Byte	Data Byte #1	Data Byte#2	Data Byte#3	Data Byte#4	CRC	CRC
Example01~FF	01	04	04	00	00	00	00	FB	84

Description of flowmeter response example

slave address: 01(address of this flowmeter)

function code: 04(read instruction)

Amount of response Byte: 04 (2 register=4 byte)

Data Byte: 00 00 00 00(Assume the instantaneous flow volume is 0)

CRC: FB 84(Calculating error correcting code according to CRC algorithm)

Definition and address of memory

How to use these charts

Read-write memory type	Function
Memory content	Describe the memory content function.
Register location	Read-write memory locations are not shared with read-only memory.
Register length	The length of variable memory. The unit is Register(2Byte).
Bits	​
Data type	The format of sending and receiving data type.
Remarks	​

Read-only memory list

Memory content	Register location	Register length	Bits	Data type	Remarks
Flowrate	0x00 0x00	2	4	float
Total	0x00 0x04	2	4	float
Flowrate*100	0x00 0x06	2	4	float
Total*100	0x00 0x0A	2	4	float
error code a	0x00 0x0E	1	2	int
error code b	0x00 0x0F	1	2	int
error code c	0x00 0x10	1	2	int
error code d	0x00 0x11	1	2	int
System Status	0x00 0x12	1	2	int
Total(64)	0x00 0x13	4	8	longlong
Dosing(float)	0x00 0x17	2	4	float
Dosing100(32)	0x00 0x19	2	4	float
Dosing(64)	0x00 0x1B	4	8	longlong
M	0x00 0x53	1	2	int
m	0x00 0x54	1	2	int
flow*100_2	0x00 0x55	2	4	float
na	0x00 0x57	2	4
total*100_2	0x00 0x59	2	4	float