RS485 PM2.5/PM10 Sensor Modbus Particle Detection Sensor Transmitter Air Quality Detection
1. PM2.5, PM10 output at the same time
485 communication (modbus) protocol baud rate: 2400.4800 (default) .9600
Data bit length: 8 bits
Parity mode: none
Stop bit length: 1 bit
Default modbus communication address: 1
Support function code: 03Parameter settings: Configured with the supplied configuration software via the 485 interface
Wiring instructions
|
Cable color |
Description |
Power
|
Brown |
Power+ (10-30vdc ) |
black |
Power - |
|
Communication |
yellow |
485-A |
Blue |
485-B |
Communication protocol
Basic communication parameters
Code |
8-bit binary |
Data bit |
8 bit |
Parity bit |
NO |
Stop bit |
1 bit |
Error check |
CRC |
Baud rate |
2400bit/s, 4800bit/s, 9600 bit/s default is 4800bit/S |
4.2 Data frame format definition
Adopt Modbus-RTU communication protocol, the format is as follows:
Initial structure ≥ 4 bytes of time
Address code = 1 byte
Noise Transmitter Instruction Manual (Type 485) V2.0
Function code = 1 byte
Data area = N bytes
Error check = 16-bit CRC code
End structure ≥ 4 bytes of time
Address code: is the address of the transmitter, which is unique in the communication network (factory default 0x01).
Function code: The instruction function of the command sent by the host. This transmitter only uses function code 0x03 (read register data).
Data area: The data area is the specific communication data. Note that the 16bits data high byte is in front!
CRC code: Two-byte check code.
Host inquiry frame structure:
Address code |
Function code |
Register start address |
Register length |
check code low |
Check code high |
1 bytes |
1 bytes |
2 bytes |
2 bytes |
1 bytes |
1 bytes |
Slave transponder frame structure
Address code |
Function code |
effective byte |
No 1 Data area |
NO2 Data area |
No N Data area |
Check code |
1 bytes |
1 bytes |
1 bytes |
2 bytes |
2 bytes |
2 bytes |
2 bytes |
Register address
Register address
|
PLC or configuration address |
content |
operation |
0000 H |
40001 |
PM2.5 Upload data is the real value |
Read only |
0000 H |
40002 |
PM10 Upload data is the real value |
Read only |
4.4 Communication protocol examples and explanations
Example: Read the PM value of device address 0x01
Inquiry frame:
Address code |
Function code |
Start address |
Data length |
check code low |
Check code high |
0x01 |
0x03 |
0x00 0x00 |
0x00 0x02 |
0xC4 |
0x0B |
Response frame: (eg read 85ug/m3 for PM2.5 and 156ug/m3 for PM10)
Address code |
Function code |
effective byte |
humidity |
temperature |
check code low |
Check code high |
0x01 |
0x03 |
0x04 |
0x00 0x55 |
0x00 0x9c |
0xEA |
0x4A |
PM2.5 calculation:
Air quality (PM2.5/P10) transmitter instruction manual (type 485) V2.0
PM2.5:0055 H (hexadecimal) = 85=> PM2.5 = 85ug/m3
PM10 calculation:
PM10:009CH (hexadecimal) = 156 => PM10 = 156ug/m3
Package includes: