Vaisala WXT535 Weather Transmitter

Overview

The Vaisala WXT535 Weather Transmitter is a compact, integrated environmental sensor designed for reliable, long-term outdoor deployment in demanding meteorological and industrial monitoring applications. Engineered for precision and robustness, the WXT535 employs Vaisala’s proprietary solid-state sensing technologies—including capacitive PTU (Pressure-Temperature-Humidity) measurement and RAINCAP acoustic precipitation detection—to deliver stable, maintenance-free performance across extreme climatic conditions. Unlike mechanical rain gauges, the RAINCAP sensor eliminates errors from evaporation, clogging, splash, or overflow by detecting raindrop impacts via ultrasonic transduction. Similarly, the integrated PTU module performs simultaneous, drift-resistant measurements of air temperature, relative humidity, and atmospheric pressure within a single sealed, field-replaceable unit—requiring no recalibration or sensor exposure during servicing. The device operates without moving parts, ensuring high reproducibility and compliance with IEC 60945 maritime environmental standards.

Key Features

• Integrated multi-parameter measurement: temperature, relative humidity, barometric pressure, and rainfall—all in one low-profile housing
• Vaisala RAINCAP acoustic rain sensor: immunity to mechanical obstruction, evaporation loss, and wetting errors; supports accurate intensity, accumulation, and duration reporting
• Vaisala HUMICAP® and BAROCAP® technologies embedded in a modular PTU unit—field-swappable without disassembly or recalibration
• Low-power design: typical current draw of 3 mA @ 12 VDC enables solar-powered operation in remote or off-grid installations
• Flexible power and communication architecture: supports 6–24 VDC input, optional heater (12–24 VDC/12–17 VAC), and multiple digital interfaces including SDI-12 v1.3, RS-232, RS-485, and RS-422
• Industrial-grade enclosure: IP65 rating (IP66 with mounting adapter), operating range from −52 to +60 °C, and storage capability down to −60 °C
• Analog input capability for integration with third-party sensors (e.g., pyranometers, external thermistors), transforming the WXT535 into a compact environmental data aggregator

Sample Compatibility & Compliance

The WXT535 is optimized for ambient atmospheric sampling under unsheltered outdoor conditions. Its calibrated measurement volumes comply with WMO (World Meteorological Organization) siting guidelines for temperature and humidity when installed with appropriate radiation shielding (e.g., Vaisala’s RM Young 41372 aspirated radiation shield). Rainfall detection conforms to ISO 9060:2018 spectral classification for Class C instruments and meets the functional requirements of ASTM D5096 for precipitation gauge accuracy validation. The device’s firmware and data output protocols support traceability and audit readiness for GLP/GMP-aligned environmental monitoring programs. While not FDA 21 CFR Part 11–certified out-of-the-box, its ASCII/NMEA 0183 and SDI-12 outputs are compatible with validated data acquisition systems that implement electronic signature, audit trail, and secure archive functions per regulatory requirements.

Software & Data Management

The WXT535 operates autonomously with configurable measurement intervals (1 s to 1 hr) and built-in data buffering. It supports both polled (ASCII query-based) and autonomous (NMEA 0183 sentence broadcast) communication modes, enabling seamless integration with SCADA platforms, IoT gateways, and cloud telemetry services. Vaisala’s proprietary ViewLog software provides configuration, diagnostics, and firmware updates via USB-to-serial interface. All output formats—including SDI-12 command-response sequences and NMEA $WIXDR sentences—are fully documented in Vaisala’s public Application Note AN-168, facilitating custom script development in Python, LabVIEW, or MATLAB environments. Time-stamped raw and processed values (e.g., 1-minute sliding rainfall intensity, cumulative total since last reset) are transmitted with consistent framing and CRC error checking, ensuring data integrity over noisy serial links.

Applications

• Automated weather stations (AWS) for hydrological modeling, flood forecasting, and agricultural decision support systems
• Environmental compliance monitoring at industrial sites (e.g., stack emission control, dust suppression verification)
• Renewable energy operations: solar farm soiling assessment, wind resource pre-feasibility studies (when paired with WXT536 or external anemometer)
• Transportation infrastructure: road surface condition prediction, airport low-visibility alerting, railway track icing monitoring
• Research-grade microclimate networks in ecological field stations, urban heat island studies, and permafrost monitoring arrays
• Maritime and offshore platforms requiring IEC 60945-compliant environmental telemetry with corrosion-resistant housing

FAQ

Does the WXT535 include wind measurement capabilities?
No—the WXT535 measures temperature, humidity, pressure, and rainfall only. For wind speed and direction, consider the WXT536 variant or integrate a separate ultrasonic anemometer such as the Vaisala WINDCAP® WMT700.
Can the RAINCAP sensor distinguish between rain, snow, and hail?
The RAINCAP detects liquid precipitation impact energy and duration; it does not classify precipitation phase. For solid-phase discrimination, pairing with a heated tipping-bucket gauge or optical disdrometer is recommended.
Is calibration documentation provided with the unit?
Yes—each WXT535 ships with a factory calibration certificate traceable to national metrology institutes (NMI), including individual sensor offset and linearity coefficients for temperature, RH, pressure, and rain volume.
What is the expected service life under continuous outdoor exposure?
With proper mounting and periodic visual inspection, the WXT535 maintains specified accuracy for ≥5 years; the replaceable PTU module extends functional lifetime beyond 10 years.
Can the analog inputs accept 4–20 mA signals?
No—the WXT535’s analog inputs are designed for 0–2.5 V or 0–5 V DC voltage sources only. External signal conditioning is required for 4–20 mA loop integration.