Read/Write Memory Read Command (03)

For large numbers, reading and writing in different formats (float32/int64) may result in a discrepancy of less than 1/10,000.

Example Command:

Format for issuing the read command (03) from the control terminal.

Byte#	1	2	3	4	5	6	7	8
Node ID	Slave Address	Function Code	Starting Address of Data to Read	Starting Address of Data to Read	Number of Registers to Read	Number of Registers to Read	CRC	CRC
Example 01~FF	01	03	00	00	00	03	05	CB

This example reads the pipe diameter data of A02 Preset Pipe Spec.

• Slave Address: 01 (Address of the flow meter)

• Function Code: 03 (Read command)

• Starting Address of Data to Read: 00 00 (Starting address of the A02 Preset Pipe Spec data)

• Number of Registers to Read: 00 03 (Read three registers starting from address 00 00)

• CRC: 05 CB (Error-checking code calculated using the CRC algorithm)

Flow Meter Response Format (03)

Byte#	1	2	3	4	5	6	7	8	9	10	11
Node ID	Slave Address	Function Code	Number of Bytes Returned	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	06	00	00	42	41	59	E5

Example Explanation of Flow Meter Response

• Slave Address: 01 (Address of the flow meter)

• Function Code: 03 (Read command)

• Number of Bytes Returned: 06 (3 registers = 6 bytes)

Data Bytes:

• 00 06 (Current type option: ASTM SCH 80 PVC)

• 00 00 (Reading A02 RS485 init)

• 42 41 (Reading A02 RS485 init)

CRC: 59 E5 (Error-checking code calculated using the CRC algorithm)