EML ARG314 Tipping Bucket Rain Gauge
The EML ARG314 is a WMO-compliant aerodynamic tipping bucket rain gauge, UK-manufactured from injection-moulded UV-stabilised material for accurate rainfall measurement in the harshest field conditions. Available in 0.1 mm, 0.2 mm or 0.5 mm per-tip resolutions with a reed-switch contact-closure output compatible with all modern data loggers.
Description
The ARG314 Aerodynamic Rain Gauge is manufactured in the United Kingdom by Environmental Measurements Limited (EML) and is the successor to the long-established ARG100. Its unique aerodynamic profile — refined over more than a decade of field research — accelerates airflow smoothly around the collector to minimise wind-induced under-catch, a well-documented failure mode of traditional cylindrical rain gauges that can reduce catch by up to 20 %.
The gauge body is precision injection-moulded from a UV-stabilised material that resists degradation from prolonged sun exposure and temperature extremes, making it suitable for permanent outdoor deployment in tropical, desert and cold-climate sites. The depth, diameter and angle of the funnel have been extensively tested to meet World Meteorological Organization (WMO) recommendations for orifice area, and each gauge is factory-calibrated to a tolerance of 2 % of the tip value against a WMO-compliant pit gauge.
Rainfall passes through a stainless-steel gauze filter and drips into a self-emptying tipping bucket. Each tip closes a reed switch to produce a single contact-closure pulse — a passive output that requires no external power for the sensor itself and is compatible with virtually any data logger, event recorder or SCADA input. The reed switch is user-replaceable as standard, and a dual reed-switch upgrade is available for redundant or differential logging.
Typical applications include:
- National meteorological service networks and reference stations
- Hydrology and catchment monitoring
- Automatic weather stations (AWS) and hydro-met sites
- Flood early-warning systems
- Industrial and utility sites requiring accurate precipitation data
- Research-grade and professional weather stations
The ARG314 is available with 0.1 mm, 0.2 mm or 0.5 mm per-tip resolution. Optional variants include factory-fitted 6 m cable, plug-terminated versions for EML internal loggers, a dual reed-switch upgrade and a siphon upgrade for improved high-intensity performance.
| Measurement | |
|---|---|
| Sensing Method | Self-emptying tipping bucket with stainless-steel gauze filter |
| Resolution (per tip) | 0.1 mm, 0.2 mm or 0.5 mm (imperial 0.005" or 0.01" available) |
| Funnel / Collector Diameter | 20.0 cm (7.87 in) |
| Funnel / Collector Area | 314 cm² (48.67 sq. in) |
| Typical Accuracy (all gauges) | ±2 % up to 25 mm/hr (Class A) |
| Accuracy — 0.1 mm gauge | ±3 % up to 50 mm/hr (Class A) |
| Accuracy — 0.2 mm & 0.5 mm gauges | ±3 % up to 120 mm/hr (Class A) |
| Accuracy with mathematical correction — 0.1 mm | ±3 % up to 500 mm/hr (Class A) |
| Accuracy with mathematical correction — 0.2 mm | ±3 % up to 1000 mm/hr (Class A) |
| Accuracy with mathematical correction — 0.5 mm | ±3 % up to 1500 mm/hr (Class A) |
| Outputs | |
| Output Type | Contact closure (reed switch), user-replaceable as standard |
| Upgrade Options | Dual reed switch upgrade available |
| Cable | Standard 6 m cable option (P-780-301 / -304 / -307); plug-terminated variants available for EML internal loggers |
| Logger Compatibility | Compatible with all modern data loggers and event recorders |
| Power Requirements | |
| Sensor Power | Passive — no supply required (reed-switch contact closure) |
| Environmental & Mechanical | |
| Operating Temperature | 0 °C to +70 °C |
| Housing Material | Injection-moulded UV-stabilised material |
| Colour | White |
| Height | 43.5 cm to 46.5 cm (with adjustable feet) |
| Weight | 2 kg |
| Mounting | Adjustable levelling feet; external levelling bubble; no base plate required |
| Certification & Compliance | |
| WMO Compliance | Yes — meets WMO recommendations for funnel area |
| Quality System | Manufactured and assembled by EML in the United Kingdom under ISO 9001 |
| Testing | Laboratory tested and outdoor field-tested against a WMO-compliant pit gauge at multiple sites |
