Longrun LRF-3300S, Руководство пользователя

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LRF-3300S Ultrasonic Transit-time Flow meter
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0AH) The sum of all of its return data is =2BH+31H+32H+33H+34H+35H+
36H+37H+45H+2BH+30H+6DH+33H+20H=2F7, The low 8-bit data of its binary is F7.
Therefore, the data of the order PRT (cr) (lf) is 12 0m3!F7 (cr) (lf), "!"For delimiters,
the preceding is the character of the summation, followed by a check code of 1 byte.
6. Usage of prefix W: W+ numeric string address code +basic command. Value range of the numeric string is 0
~ 255, except 13 (0DH carriage return ), 10 ( 0AH line feed ). If the instantaneous velocity of No. 123
flow meter is to be accessed, the command W123DV (cr)(lf) can be issued. The corresponding binary
code is 57H, 31H, 32H, 33H, 44H, 56H, 0DH, 0AH, only the same instrument with the same address of
the Internet address and command will send back the data.
7. W and P commands can be used in combination, for example, W123PRT +, which means that the
instrument that reads the network address is the cumulative value of the instrument with 123, and its
return data has eight accumulations and checksums."s" expresses ON or OFF or UD. For example,
"TR:ON, RL:ON" expresses that the OCT and relay are in an actuated status; "TR:UD
，
RL:UD"
expresses that the OCT and relay are not actuated.
8.4.2. MODBUS-I Communication Protocol
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.
1. MODBUS-I 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
2. MODBUS Protocol function code 0x03 usage
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 ( Data ) CRC ( Verify )
N* = Data register number
3. MODBUS Protocol function code 0x06 usage