USB temperature & humidity sensor with datalogging software: Dracal TRH450 as an alternative to OMEGA RH-USB
When selecting a USB temperature and humidity sensor, the Omega RH-USB has been a common choice in industrial and laboratory settings. The Dracal TRH450 offers an alternative with improved specifications and capabilities. This article compares both products across key criteria to help you determine which sensor meets your requirements.
What task are these sensors designed to perform?
Both sensors measure environmental temperature and relative humidity via a USB connection to a computer.
Omega RH-USB:
- Designed for wall or duct mounting in standard environmental monitoring applications
- Temperature range: -17°C to +49°C
- Comes with a 2-meter integral USB cable and 316 stainless steel housing
Dracal TRH450:
- Designed for applications requiring extended temperature ranges or additional physical protection
- Temperature range: -40°C to +125°Cfor the probe
- Features an aluminum probe with internal particle filter and a replaceable standard 1-meter USB cable
Both sensors include free software for data logging and visualization.
Accuracy and performance
| Specification | Dracal TRH450 | Omega RH‑USB |
|---|---|---|
| Temperature accuracy | ±0.1°C | ±1°C |
| Temperature range (probe) | –40°C to +125°C | -17°C to +49°C |
| RH accuracy | ±1.5% RH | ±3% RH (15-90% range) |
| RH range | 0-100% | 2-98% |
Conclusion: The TRH450 offers higher precision and operates across a wider temperature range.
Physical construction
| Feature | Dracal TRH450 | Omega RH‑USB |
|---|---|---|
| Housing material | ABS (cable/electronics housing) | 316 stainless steel |
| Probe material | Anodized aluminum with PTFE membrane | 316 stainless steel |
| IP rating | IP51 | IP66 (NEMA 4) |
| Cable type | Standard USB-A to Mini-USB | Integrated and shielded |
| Cable length | 1 meter (user-replaceable with any length) | 2 meters (fixed) |
| Particle filter | >99.99% efficiency for particles ≥200 nm | Removable stainless steel filter |
| PCB protection | Conformal coating (moisture, rust, corrosion) | Standard |
| Warranty | 3 years | 1 year |
Conclusion: The Omega sensor offers full IP66 rating and a longer fixed cable. The Dracal sensor provides a user-replaceable cable (any length possible), enhanced particle filtration (>99.99% at 200nm), conformal PCB coating for harsh environments, and 3X the warranty period.
Data logging and software
| Feature | Dracal TRH450 (DracalView) | Omega RH‑USB (TRH Central) |
|---|---|---|
| Cost | Free | Free |
| Operating aystems | Windows, macOS, Linux | Windows only |
| Setup yime | <3 minutes | Requires Windows installation |
| Simultaneous aensors | Unlimited (all types) | Designed for individual sensors |
| Logging interval | Configurable (0.5 seconds to 1 year) | Configurable |
| Data export | Text, CSV, Excel, .png | CSV, Excel, graphing |
Conclusion: Both provide free data logging software. DracalView supports multiple operating systems and can manage multiple sensors simultaneously. TRH Central is Windows-specific and designed primarily for single-sensor use.
Calibration
| Feature | Dracal TRH450 | Omega RH‑USB |
|---|---|---|
| Factory calibration | Yes | Yes |
| Field calibration | Yes (on -CAL models, 3-point user calibration) | No |
| Recalibration options | User can perform (CAL models) or send to accredited lab | Must return to Omega |
| Calibration downtime | Zero (when using CAL models) | Days to weeks (shipping + service time) |
| NIST Traceable Certificates | Available via ISO 17025 labs (10-15 business days) | Available (contact Omega for details) |
Conclusion: The TRH450’s user calibration option eliminates downtime for recertification. Dracal offers an expedited calibration service of <5 days for calibration and recalibration of its products, but any accredited laboratory can also perform the work. Dracal also offers an ecosystem of partner laboratories.
Integration and API
| Feature | Dracal TRH450 | Omega RH‑USB |
|---|---|---|
| Command-line Tools | Yes (dracal-usb-get included) | Limited (command reference available) |
| Serial COM | Yes (VCP option) | No |
| API | REST API (with SensGate + VCP sensors) | Telnet/Serial commands |
| Code Examples Provided | Python, C, C++, C#, Java, Node.js, Bash, VBA | None (user must develop) |
| LabVIEW Integration | 4 ready-made .vi files (USB CLI, VCP serial, Wi-Fi CLI, Wi-Fi serial) | Community-developed examples only |
| API Documentation | Comprehensive with step-by-step guides | Basic command reference PDF |
| Communication Modes | USB (HID) or VCP (Virtual COM Port) | USB only |
| Integration Complexity | Low (copy/paste examples work immediately) | High (requires custom USB development) |
Conclusion: The TRH450 includes more integration resources out of the box. The RH-USB requires users to develop custom integration code or use the provided TRH Central software.
Wireless Options
| Feature | Dracal TRH450 | Omega RH‑USB |
|---|---|---|
| Native Wireless Solution | Yes (SensGate gateway, sold separately) | No |
| Wireless Technology | Wi-Fi (2.4GHz) + Ethernet | N/A |
| Setup Time | <5 minutes without IT support | N/A |
| Network Modes | Client mode or Access Point mode | N/A |
| Sensors per Gateway | Up to 7 USB ports (expandable with hubs) | N/A |
| Internal Data Logging | Yes (3GB memory for standalone logging) | N/A |
| Configuration Interface | Web-based | N/A |
| Cloud Dependency | None (on-premise solution) | N/A |
Conclusion: For wireless deployments, the TRH450 has a purpose-built solution, that is the SensGate. The RH-USB would require a PC at each monitoring location or a custom USB-over-IP solution.
Pricing
| Item | Dracal TRH450 | Omega RH‑USB |
|---|---|---|
| Base sensor | From USD $223.99 | USD $331.78 |
| VCP (Virtual COM) model | From USD $249.99 | Not available |
| Software | $0 | $0 |
| NIST traceable certificate | Available (10-15 business days, or <5 days with express option) | Available (contact Omega) |
Prices as of November 2025. Contact manufacturers for current pricing.
Conclusion
Both sensors serve the temperature and humidity monitoring market with different specifications and approaches. The Dracal TRH450 offers higher accuracy, a wider operating range, field calibration capability, and native wireless options at a lower price point. The Omega RH-USB provides a solution from an established brand with full IP66-rated housing. Both products include free software and provide NIST-traceable calibration options.
Choose Dracal TRH450 when you need:
- Best measurements accuracy and operating range
- Field calibration capability
- Multi-sensor deployments with synchronized logging
- Wireless monitoring without dedicated PCs at each location
- Integration into custom software (extensive code examples provided)
- Cross-platform operation (Windows, macOS, Linux)
Choose Omega RH-USB when:
- You have existing Omega equipment or prefer their brand
- Full IP66-rated housing is specifically required
This comparison is based on publicly available specifications as of November 2025. Always verify current specifications and pricing with manufacturers before purchasing.
Always offered at no extra charge with our products!
EASY TO USE IN YOUR OWN SYSTEM
- Ready-to-use, accurate and robust real-time data flow
- Choose the interface that works best for you (CLI, virtual COM, REST API)
- Code samples available in 10+ programming languages (Python, C/C++, C#, Java, Node, .Net, etc.)
- Operates under Windows, Mac OS X and Linux
- Usable with LabView (CLI guide, Virtual COM guide)
- All tools packaged within one simple, free of charge, DracalView download
FREE DATA VISUALIZATION, LOGGING AND CALIBRATION SOFTWARE
- Get up-and-running in less than 3 minutes
- Operates under Windows, Mac OS X and Linux
- Real-time on-screen graphing and logging
- Log interval down to 0.5 second and configurable units (°C, °F, K…)
- Simultaneous use of unlimited Dracal sensors supported
- Simple user-calibration (products with the -CAL option)
- Connectivity with SensGate Wi-Fi/Ethernet gateway
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