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MaxiMet GMX300 Weather Station
  • MaxiMet GMX300 Weather Station

GMX300 Weather Station for Temperature, Humidity & Pressure

Quick Overview

The MaxiMet GMX300 is a Compact Weather Station. The sensors are mounted inside three double louvered, naturally aspirated radiation shields, taking Ambient Temperature, Relative Humidity and Barometric Pressure Readings. Calculated Dew Point, Wet Bulb and Heat Index readings can also be provided via the RS232, RS422, RS485. SDI12, NMEA and Modbus output strings.

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GMX300 Dimensions

Temperature & Relative Humidity

  • Air Temperature and Relative Humidity
  • Calculated Dew Point and Absolute Humidity
  • Wet Bulb Temperature (When Temperature <-20 and <50°C, 5-99%RH)

Barometric Pressure

  • Barometric Pressure
  • Pressure at Sea Level
  • Pressure at Station
  • Air Density


  • Compass Reading (0-359° Magnetic North)
  • X -Tilt. +ve East, -ve West
  • Y -Tilt. +ve North, -ve South
  • Z Orientation, +1 Normal Upright, -1 Inverted Position
  • X & Y Can Provide 2 Decimal Points for Easy Installation.

Additional Parameters

  • Supply Voltage
  • System Status
  • System Time and Date
  • Custom User Information (up to 16 character)

Parameter Specifications

Parameter Range Resolution Accuracy Units of Measure
Compass 0-360° ±3° Degrees
Temperature -40 to +70°C 0.1°C ±0.3°C °C, F or °K
Humidity 0-100%RH 1%RH Typically ±2%RH %RH, g/m²
Dew Point -40 to +70°C 0.1°C   °C, F or °K
Pressure 300-1,250hPa 1hPa ±0.4hPa (Absolute)
±0.8hPa (Relative)
hPa, mBar, mmHg, InHg

GMX300 Specifications

Output Rate: 1Hz, 1 reading per minute, 1 Reading per hour, or Polled Mode
Digital Comms: RS232, RS485, RS422, SDI-12, NMEA, Modbus, ASCII
Power Supply: 5-30vDC
Consumption @ 12vDC: 5mA
IP Rating: IP66
Operational Temperature Range: -35 to +70°C
CE Marking: Yes
Dimensions: 155 x 142 x 142mm
Weight: 0.48Kg
Origin: UK
Warranty: 24 Months

Availability: Stock Item


Components / Downloads

For further information, technical advice, or a quotation please call or email us. If you are not sure which product you need one of our technical sales advisors will be happy to discuss your application. We also accept company purchase orders by fax or post. Credit card orders can also be placed over the phone for any product.

GMX300 Compact Weather Station

MaxiMet GMX300 Compact Weather Station. Measured Parameters: Air Temperature, Relative Humidity and Barometric Pressure. Derived Parameters: Dew Point, Wet Bulb Temperature, Heat Index, Absolute Humidity, Air Density and Pressure at Sea Level. Outputs: RS232, RS422, RS485 (ASCII), SDI-12, NMEA, Modbus. Power Supply: 5-30vDC (Consumption 5mA @ 12vDC).

View FileDatasheet
   Size: (317.04 KB)
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MaxiMet Configuration Cable
1.8m RS232 to USB Configuration Cable for the Maximet Weather Stations. Configuration cable provides 5V power to the Maximet and allows for the 9-way Maximet connector to connect to a PC for the initial set up and configuration. GMX should be in Safe Mode to allow for configuration and the adaptor cable is not weatherproof and should not be used one units are installed on site.
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Mounting Bracket
Anodized Aluminium Bracket for mounting to pole and wall. Includes an aluminium sensor adaptor for WindSonic or MaxiMet, fully anodised to reduce corrosion. The Bracket uses a mounting clamp suitable for attaching to a vertical pipe with a diameter of 30-58mm. When mounting the MaxiMet, consider the position, orientation and alignment of the unit. Mount at the top of a pipe to ensure a clear unobstructed measurement view. Kit includes stainless steel mounting bolts, multiple earth points and wall / pole mounting kit
View FileDatasheet
   Size: (887.85 KB)
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Portable Tripod
Weather station tripod mounting kit with 2m pole. The legs on this tripod are not adjustable for uneven surfaces and ground should be levelled prior to installation. ¼" stake kit (M-SKB), ½" Stake kit (M-SKA), Guy wire kit (M-GWA) and Grounding kit (M-GKA) are available separately.
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Tripod Accessories
Mounting adaptor for connecting the WindSonic wind sensors or MaxiMet compact weather stations to the M-TPB tripod. Provides a direct mounting to the top of the tripod for an unobstructed placement of the mounted sensors. Ideal for solar radiation, wind and rain sensors.
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Mounting adaptor to protect the cable of the WindSonic wind sensors or MaxiMet compact weather stations as it exits the bottom of the M-TPB tripod.

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Guy Wire Kit for the M-TPA or M-TPB tripods. Can be secured to Stakes spaced around the 2m tripod at a distance of 3 or 4 m, or to the tripod legs of the 3m tripod. This helps secure the tripod in place and reduces any movement due to wind.
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Stake Kit for the M-TPB tripod. Allows the Guy Wires to be secured to Stakes spaced evenly around the tripod at a distanced of 3 to 4m. Stake Kit includes 3 x ½" Stakes and S-Hooks.
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Spare 9 way mating connector. Suitable for all WindSonic plastic versions, WindSonic M Non-Analogue and MaxiMet sensor and weather stations.
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Cable assembly to connect Windsonic or MaxiMet unit to external data logger or display. Includes inline multipole connector for WindSonic or MaxiMet and flying leads, cable length 6.5 metres. Other lengths available on request.
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