SPECIFICATION
product name： | VOC transmitter |
Model： | MAQ15 |
version： | V1.0 |
Creator： | He Genwen |
reviewed by： | Yuan Chao |
Product Introduction
The VOC transmitter MAQ15 uses a highly sensitive air quality sensor to detect the concentration of VOC gas in the current environment. Using RS485 interface and standard MODBUS-RTU protocol, it can achieve multi-point monitoring, networking, and long-distance data transmission. Suitable for various places, especially in public places, factories, warehouses, and other places that require VOC monitoring.
For the convenience of engineering networking and industrial applications, this module adopts the MODBUS-RTU communication protocol widely used in industry, supporting secondary development. Users can use any serial communication software to query and set module data based on the communication protocol.
Technical Parameter
Serial Number | parameter | TECHNICAL INDEX |
1 | Detect gas | Toluene, ethanol, H2S, NH3, H2, etc |
2 | protection grade | IP65 |
3 | measuring range | 0-500ppm |
4 | resolution ratio | 1ppm |
5 | measurement error | ± 3%FS ( 25℃) |
6 | response time | <6 minute |
7 | output signal | Modbus RS485 |
8 | Supply Voltage | DC7V~36V |
9 | operation temperature | -10℃ ~ 65℃ |
10 | Working humidity | 0-90%RH |
11 | Display method | not have |
12 | Output Load | RS485@120Ω |
13 | Installation method | Wall Mount |
14 | weight | <300g |
15 | size | 117mm*87mm*51mm |
Wiring method：
As shown in the figure on the right, the device comes with a four chip lead wire, and the wiring should follow the following requirements:
The brown wire represents the positive polarity of the power supply，
The black line represents the negative power supply；
The yellow line represents RS485+/A,
The blue line is RS485-/B
note：
1、Avoid exposure to silicone vapors. If organic silicon vapor is adsorbed on the surface of the sensor, the sensitive material of the sensor will be enveloped, suppressing the sensitivity of the sensor and cannot be restored. Sensors should be avoided from being exposed to silicon adhesives and hairPlaces where silicone rubber, putty, or other silicone plastic additives may exist。
2、Avoid exposure to highly corrosive environments. Sensors exposed to high concentrations of corrosive gases (such as H2S, SOX, Cl2, HCl, etc.) not only cause corrosion or damage to heating materials and sensor leads, but also irreversible changes in the properties of sensitive materials。
3、Avoid exposure to environments contaminated with alkali, alkali metal salts, and halogens。
4、As a VOC detection method used in important work environments, it is necessary to conduct regular testing, usually every 3 months to 6 months, to ensure the sensitivity of the sensor to VOC。
Communication protocol
All device operations or reply commands are in hexadecimal data. Default communication baud rate: 9600, 8 N 1。
Basic format for sending commands: Time interval: ≥ 50ms
xx | 03 | 00 | 00 | 00 | 01 | CRC_L | CRC_H |
Device Address | function code | Register address | Length | CRC check bit |
When the device address is unknown, 0xFA can be used as the universal query address,
The command is： FA 03 00 00 00 02 D1 80
When the address is 1，
Read Data Command： 01 03 00 00 00 02 C4 0B
Return data ： 01 03 04 00 15 00 00 CRC_L CRC_H
In the above data, 01 represents the address, 03 represents the read command function code, and 04 represents a data length of 4 bytes. As the length of the measurement point data takes up two bytes, for example, the first data is 00 15, which is converted to 10 base and is 21, which means the actual value is 21 PPM. In the configuration software, register comparison table:
Serial Number | name | Register address | types of | Value Range |
1 | VOC concentration register | 00 00 | unsigned int | 0 ~ 1000 |
Change Device Address Command：
When the device address is unknown, a universal address FA can be used：
The command is： FA 06 0B 00 00 02 0A 2F，
Among them, 02 is the address to be modified。
06 is the function code for modifying addresses
0B is the auxiliary command number。
00 00 Fixed value, cannot be changed。
When the device address is 1, change it to address 2, and the command is as follows:
01 06 0B 00 00 02 0A 2F
Device response returned data: 02 25 01 02 90 06, indicating successful address change。
Note: The default factory device address is 4,
By default, the serial port parameter is 9600 8 N 1, and the number of stop bits can be modified by command：
The function code is 07, and the default first address is 04. The modification command is as follows
Use the current address to modify the stop bit to 1 bit：04 07 00 00 00 00 B4 5F
Return data after successful setup：04 07 01 00 B1 45
Use the current address to modify the stop bit to 2 bits：04 07 00 00 00 01 75 9F
Return data after successful setup：04 07 01 01 70 85
Use universal address to modify stop bit to 1 bit： FA 07 00 00 00 00 A1 81
Return data after successful setup： FA 07 01 00 80 AD
Use universal address to modify stop bit to 2 bits： FA 07 00 00 00 01 60 41
After successfully setting the stop bit to 2 bits using a universal address, return data： FA 07 01 01 41 6D
View the current number of serial port stop bits：04 08 00 00 00 00 E0 5E
Return data：04 08 01 xx CRCL CRCH
Use Universal Address Query： FA 08 00 00 00 00 F5 80
Return data： FA 08 01 xx CRCL CRCH
When the returned xx is 00, the stop bit is 1 bit, and when it is 01, the stop bit is 2 bits.
