Airmar 120WX Ultrasonic Weather Station

Overview

The Airmar 120WX Ultrasonic Weather Station is a discontinued but technically significant marine-grade environmental sensor platform engineered for continuous, high-reliability meteorological monitoring in harsh offshore and industrial environments. Designed using ultrasonic time-of-flight principles, it measures wind speed and direction without moving parts—eliminating mechanical wear, icing susceptibility, and calibration drift associated with cup-and-vane anemometers. Its compact, low-profile housing enables integration into fixed infrastructure including offshore drilling platforms, coastal lighthouses, port authority control towers, and research buoys. Though superseded by the 110WX series for new deployments, the 120WX remains referenced in legacy system documentation, maintenance protocols, and compliance audits where installed base continuity is required. It delivers synchronized measurements of wind vector, barometric pressure, ambient air temperature, wind chill index, and—when equipped—relative humidity. All data are timestamped and output via industry-standard marine communication protocols to ensure interoperability with bridge navigation systems, SCADA networks, and environmental data loggers.

Key Features

• Ultrasonic wind sensing with no rotating components—ensures long-term stability and minimal maintenance in salt-laden or particulate-rich atmospheres
• Modular humidity sensor design: field-replaceable RH module with quick-connect interface and sealed gasketing (IPX4 rating when installed)
• Dual-voltage DC input (12–24 VDC) with reverse-polarity protection and transient surge suppression per IEC 61000-4-5 Level 3
• Power efficiency optimized for solar-battery remote sites: average current draw 50% reduction versus prior-generation Airmar sensors
• Triple-output architecture: simultaneous RS232 (NMEA 0183), RS422 (NMEA 0183 differential), and CAN Bus (NMEA 2000) interfaces—enabling redundant telemetry paths and multi-system integration
• Mechanical mounting flexibility: 1″-14 UNS threaded base or optional ½” NPT adapter; compatible with standard marine mast brackets and vibration-dampened pole mounts
• Internal heating element option (factory-installed) mitigates condensation and frost accumulation on transducer faces under sub-zero or high-humidity conditions

Sample Compatibility & Compliance

The 120WX is certified for continuous operation in ambient temperatures ranging from –25 °C to +60 °C and relative humidity up to 100% non-condensing. Its IPX6-rated enclosure meets IEC 60529 requirements for protection against powerful water jets—critical for deck-mounted installations subject to wave wash and high-velocity rain. When the optional humidity sensor is installed, the unit complies with IPX4 (splashing water resistance). All firmware and data formatting adhere strictly to NMEA 0183 v4.10 and NMEA 2000 v2.00 specifications, ensuring traceable message structure, checksum integrity, and PGN consistency. The device supports GLP-aligned audit trails when used with WeatherCaster software configured for logging with UTC timestamps and sensor metadata embedding.

Software & Data Management

WeatherCaster PC software (included on CD-ROM) provides real-time visualization, configuration parameter adjustment, firmware update capability, and raw data export in CSV/TSV format. It supports configurable polling intervals (1–60 s), NMEA sentence filtering, and alarm thresholds for wind gust exceedance or sensor timeout events. Data files include embedded header metadata: sensor serial number, calibration date, firmware revision, and UTC synchronization status. While not FDA 21 CFR Part 11 compliant out-of-the-box, the software can be deployed within validated IT environments where electronic records are governed by SOPs requiring user authentication, change logs, and backup verification.

Applications

• Offshore oil & gas operations: real-time wind vector input for crane load management and helicopter landing zone safety assessments
• Port authority environmental monitoring: integration with VTS (Vessel Traffic Services) for berth assignment under crosswind constraints
• Coastal research stations: long-term climate trend logging with pressure-temperature-wind correlation analysis
• Renewable energy site assessment: preliminary wind resource characterization prior to LiDAR or met-mast deployment
• Maritime training simulators: hardware-in-the-loop weather input for bridge team decision-making drills

FAQ

Is the 120WX still supported for calibration or repair?
Yes—Airmar continues to honor calibration certificates and provide component-level service for units within their documented 10-year operational lifespan, subject to parts availability.
Can the 120WX output data directly to a PLC or SCADA system?
Yes—via RS422 or CAN Bus outputs, provided the host system implements NMEA 0183 or NMEA 2000 protocol stacks with appropriate baud rate and message parsing logic.
What is the maximum recommended cable length for RS422 operation?
Up to 1,200 meters at 4,800 bps; performance degrades above 9,600 bps beyond 300 meters without signal repeaters.
Does the unit require periodic recalibration?
No routine recalibration is specified; however, annual verification against traceable standards (e.g., ISO/IEC 17025-accredited wind tunnel) is recommended for metrological assurance in regulatory contexts.
Is the WeatherCaster software compatible with modern Windows OS versions?
WeatherCaster v3.x runs natively on Windows 10 and 11 via compatibility mode; virtual machine deployment is advised for Windows Server environments.