OSi’s APG-815-DS (All Precipitation Gauge) uses proven optical scintillation technology and  offers many performance and maintenance advantages over traditional tipping bucket and weighing type rain gauges. 

In addition to rain and snow water equivalent rate and accumulation the APG-815-DS report present weather codes in NWS and WMO formats.  Traditional rain and precipitation gauges cannot report present weather codes.

Adaptive Heater Technology (AHT) is used to conserved power.  The lens heaters are only energized when needed.  This mean the APG-815-DS is appropriate for solar powered installations.    Solar power combined with OSi cellular phone makes the APG-815-DS ideal for remote installations and networks.

Advantages include:

  • Measurement of instantaneous precipitation rate; rainfall as light as 0.1 mm/hr. easily measured; no evaporation errors; can handle extremely high rain rates > 500mm/hr.; no overflow or mechanical limits to worry about
  • No moving parts; operates 24/7 under harsh field conditions. No antifreeze chemicals
  • Dust / dirt on lenses does not affect measurement;  ultra-low maintenance
  • Wind does not create sampling problems.  Slant path rain errors are negligible.
  • RS- 232 digital output allows instant / detailed analysis of event
  • Functions in all weather; our sensors are operating on every continent year-round (including Antarctica)
  • Intelligent sensor; automatic correction and continuous internal monitoring; operates unattended
  • Pays for itself in maintenance & replacement costs alone; no on-site monitoring needed; lasts for years
  • Flexible mounting, even on moving platforms (buoys / shipboard); nominal 12VDC power

OSi’s sensors have more than 600 million hours of proven field operation in all climates. MTBF (Mean Time Between Failure) for OSi instruments is greater than 80,000 hours. The APG® operates unattended 24 hours a day, 7 days a week. The instrument uses proprietary algorithms that eliminate the need for frequent calibration. Field calibration every two years is typical. The APG® has AGC (Automatic Gain Control) to compensate for signal loss. The sensor also employs a comprehensive self-test that updates once per minute and reports any potential problems in the output message.




  • Additional Capability: Reports Present Weather Codes.
  • Superior Technology: APG® uses Optical Scintillation which is superior to other methods; measures true rain rate
  • Long-term reliability: operates unattended 24 hours/day, 7 days/week
  • Low maintenance
  • Adaptive Heater Technology (AHT): ideal for solar operation.
  • Data access: Low cost cellular modem option
  • Self-diagnostics & Testing: Continuously monitors performance and informs user of trouble 



  • Cellular modem option, consult factory
  • Solar Power Optional, consult factory
  • PSB-815 AC Power Supply & Junction Box®
  • QCS-815 QwikCollect Software: Collects, displays, archives data (compatible w/ all Windows systems)
  • LDM Limited Distance Modem: for distances> 100 ft. (max = 7 miles). 

Performance Specification

Rain Dynamic Range

N/A 0.1 to 500 mm/hr

Rain Accumulation

N/A 0.001 to 999.999 mm

Rain Accuracy

N/A 5% Accumulation

Rain Resolution

N/A 0.001 mm

Output Format

N/A RS-232 Serial I/O, simple polled protocol

Snow Dynamic Range

N/A 0.1 to 50.mm/hr

Snow Accumulation

N/A 0.001 to 999.999 mm

Snow Accuracy

N/A 10% Accumulation

Snow Resolution

N/A 0.001 mm

NWS Present Weather Codes

N/A Precipitation, Rain, Snow

WMO Table 4680 Present Weather Codes

N/A Precipitation, Drizzle/Freezing Drizzle, Rain/Freezing Rain, Snow

Data Update Rate

N/A Once per minute

Measurement Technique

N/A Optical Scintillation

Electronic Specification

Supply voltage

N/A 12 VDC


N/A 300 – 400 mA (Depends on Ambient Temperature)

Signal Output


Transient Protection

N/A All power & signal cables protected

Environmental Specification


N/A -40° to 50° C (-40° to 122° F)


N/A 0-100%

Precipitation / Dust

N/A NEMA 4 type protection

Physical Specification

Head Size

N/A 730 x 102 x 254 mm (29 x 4 x 10 inches)

Head Weight

N/A 3 kg (6.6 lbs.)

Cable Length

N/A 15m (48 ft)