CO2
A54-24 CO2 Sensor
Dedicated NDIR CO2 sensing solution for demand-controlled ventilation, fresh-air units and HVAC air quality management. It supports RS485 and UART interfaces, with expandable Modbus protocol support.
Read more
PRODUCT FEATURES
A54-21 PM2.5 Sensor
- Dedicated PM2.5 Monitoring: Laser scattering technology measures particulate matter for HVAC systems, fresh-air units, air handling units and indoor air quality monitoring.
- Particulate Measurement: Measurement range: 0–999 µg/m³, with 1 µg/m³ resolution. Accuracy: ±15 µg/m³ at concentrations ≤100 µg/m³ and ±15% above 100 µg/m³.
- RS485 Integration: 12–24 VDC power supply and RS485 communication through a GH1.25-4P locking connector support integration into ventilation and environmental control equipment.
- Compact HVAC Design: 66.4 × 51.4 × 19 mm PC+ABS V0 flame-retardant housing, with standby power consumption ≤1 W and power consumption ≤3 W.
TECHNICAL DATA
A54-21 PM2.5 Sensor Specifications
Product & Electrical
- Product Name
- A54-21 PM2.5 Sensor
- Model
- A5421
- Functions
- PM2.5 monitoring
- Operating Voltage
- 12–24 VDC
- Operating Current
- Average: 35 ± 5 mA @ 12 VDC; Peak: <150 mA (10 ms), at room temperature
- Standby Power Consumption
- ≤1 W
- Power Consumption
- ≤3 W
PM2.5 Detection
- Sensing Principle
- Laser scattering technology
- Measurement Range
- 0–999 µg/m³
- Resolution
- 1 µg/m³
- Accuracy
- ≤100 µg/m³: ±15 µg/m³; >100 µg/m³: ±15%
Mechanical & Communication
- Dimensions
- 66.4 × 51.4 × 19 mm
- Housing Material
- PC+ABS, V0 flame-retardant
- Communication
- RS485
- Interface
- 4-pin socket (+ / A+ / B− / GND)
- Physical Connector
- GH1.25-4P locking connector
- Operating Environment
- −10°C to 50°C, 0–95% RH, non-condensing
- Storage Environment
- −20°C to 65°C, 0–99% RH, non-condensing
Note: The matching GH1.25-4P locking terminal cable should be prepared by the user for connection.
Document: MAXMAC-A5421-EN Rev.1
TECHNICAL DATA
A54-21 Datasheet Downloads
Name
Type
Format
Size
Download
A54-21 PM2.5 Sensor DatasheetDatasheetPDF2.9 MB
T/H
A54-25 Temperature and Humidity Sensor
Dedicated temperature and relative humidity sensing for HVAC environmental monitoring, ventilation control and indoor comfort management. It supports RS485 and UART interfaces, with expandable Modbus protocol support.
Read moreHVAC
A54-22 3-in-1 Air Quality Sensor
Built on our IAQ multi sensor platform, the A54-22 integrates PM2.5, temperature and humidity sensing for particulate monitoring, ventilation systems and indoor comfort management. It supports RS485 and UART interfaces, with expandable Modbus protocol support.
Read moreHVAC
A54-23 4-in-1 Air Quality Sensor
Built on our IAQ multi sensor platform, the A54-23 integrates PM2.5, CO2, temperature and humidity sensing for fresh-air units, AHU equipment and commercial HVAC control. It supports RS485 and UART interfaces, with expandable Modbus protocol support.
Read moreHVAC
A54-20 5-in-1 Air Quality Sensor
Our complete IAQ multi sensor platform integrates PM2.5, CO2, TVOC, temperature and humidity for fresh-air units, AHU systems and smart ventilation control. It supports RS485 and UART interfaces, with expandable Modbus protocol support.
Read more
RELATED RESOURCES
View All
Related Particulate Matter Sensor Resources
Application Scenarios of PM2.5 Sensors in Vehicles
Learn how PM2.5 sensors support independent cabin and outside-air monitoring, automatic recirculation control, purifier activation, and cabin-filter life evaluation.
Air Quality Monitoring Solution for HVAC Applications
Explore room-level air-quality monitoring, HVAC linkage, fresh-air coordination, and closed-loop control using integrated air-sensor data.
Multi-in-One Air Quality Module System Design
Review PM, CO2, temperature, humidity, and gas-sensor integration, including system connection, component selection, and calibration challenges.
Automotive vs Industrial Air Quality Sensors
Compare environmental demands, calibration, interfaces, validation priorities, and PM data use across automotive and industrial sensing projects.
Provide Your Details for Professional Product Consultation
Our product experts will provide the most suitable air solutions and product recommendations.
