Product
DVM
In-duct air quality monitor with RS-485 Modbus RTU BMS integration and independent LoRaWAN data egress
Overview
The DVM is Devlabs' in-duct air quality monitoring platform. It reads a comprehensive sensor suite directly from the airstream and presents the data via two independent paths: RS-485 Modbus RTU for direct BMS integration, and LoRaWAN for independent cloud visibility.
The independence of the two data paths is a deliberate design principle. BMS integration does not depend on the Devlabs platform; Devlabs platform access does not depend on the BMS or the building's IT network. This is particularly valuable in OT environments where IT/OT separation policies prevent cloud routing of BMS data, and during commissioning — where cloud visibility can be established before BMS integration is complete.
In addition to raw sensor readings, the DVM computes two derived composite indices: CAI (Clean Air Index) and VG (Ventilation Degree). These are available on the Modbus register map and on the Devlabs platform dashboard, and can be used directly by a BMS for demand-controlled ventilation logic without requiring any custom computation in the BMS controller.
Capabilities
Key features
RS-485 Modbus RTU — native BMS protocol
Exposes sensor readings and derived indices directly via RS-485 Modbus RTU (slave address 107, 9600 baud, 8N1). No gateways, no protocol converters — a standard 2-wire cable to your BMS controller is all that is required.
Independent LoRaWAN data egress
An independent LoRaWAN data path transmits the same data to the Devlabs platform without touching the BMS or the client IT network. The two paths are entirely independent — BMS integration does not depend on the platform, and platform access does not depend on the BMS.
Devlabs in-duct sampling spear
A Devlabs-designed sampling spear passes through a small access hole in the ductwork and draws a representative sample directly from the airstream. No duct modification is required beyond the access hole itself.
CAI and VG derived indices
The DVM computes and exposes two composite indices: CAI (Clean Air Index) and VG (Ventilation Degree). Both are available on the Modbus register map and on the Devlabs platform dashboard alongside the underlying measurement data.
Standard BMS power supply
Operates on 9–24V DC — compatible with the supply typically available at a BMS controller panel. No separate power supply or specialist electrical work required.
Cleanroom particle counting (optional)
With the DL-S-OPC5K module, the DVM adds optical particle counting across ISO 14644-1 size fractions — supporting class 7, 8, and 9 cleanroom classification.
Specifications
Technical specifications
| Form factor | Wall-mount enclosure with sampling spear for in-duct installation |
| Power | 9–24V DC |
| Primary interface | RS-485 Modbus RTU — slave address 107, 9600 baud, 8N1 |
| Secondary interface | LoRaWAN via DL-LN-485 (LoRaWAN transmitter, always included) |
| LoRaWAN network server | The Things Industries (TTI) |
| Data platform | The Devlabs platform |
| Standard sensor module | PM1/PM2.5/PM4/PM10, particle number, T/RH, CO₂, eVOC index, NOₓ index (DL-S-IAQ66) |
| Averaging window | 15 s (default, configurable) |
| Derived indices | CAI (Clean Air Index), VG (Ventilation Degree) |
| Optional: High-fidelity VOC | Photoionisation VOC module (DL-S-VOC) |
| Optional: Cleanroom particle | Optical particle counter — ISO 14644-1 size fractions (DL-S-OPC5K) |
| In development | In-duct T/RH probe (DL-P-TRH-DUCT) — contact Devlabs for status |
| OTA firmware | In development — currently requires physical access |
| LoRaWAN transmitter housing | Currently in a separate external enclosure alongside the DVM |
| Limitations | Not suitable for sub-minute data intervals via LoRaWAN. |
Specifications subject to change without notice. Contact Devlabs for the current datasheet.
Ecosystem
Works alongside
Devlabs data platform
All Devlabs hardware connects to the same cloud platform — one interface for real-time monitoring, alarms, and API access across your entire deployment.
Platform overview →Get in touch
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Our team can scope your monitoring requirements, recommend a configuration, and give you an indicative price within 48 hours.