Designed for fully automatic remote operation, the Model TPC-3000 Total Precipitation Collector consists of a collection vessel, a motor-operated lid and a precipitation sensor. The collection vessel is normally kept covered by the lid during periods of non-precipitation. The user periodically visits the system to recover the precipitation sample for off site lab analysis. A next-generation, CPU-managed precipitation sensor produces the open/closed decision that controls the motor-gearbox assembly.

Often the earliest phases of a precipitation event contain the highest concentrations, and this historical lack of sensitivity has biased sampling. The precipitation sensor represents a major improvement over older technology where the earliest light precipitation events are often missed.

An Infrared Data Associationâ (IrDA) data port permits interaction with the system to view recent operational event history on a Palm handheld. The TPC-3000 is also expandable, accommodating up to two additional slave systems for multiple chemical assays such as Mercury deposition.

The TPC uses a sophisticated dual technology precipitation sensor that sets it apart from other precipitation collectors. A dual beam, near IR optical sensor, uses synchronous detection to detect precipitation. A second, heated dual grid sensor detects very light precipitation events and also logically qualifies the optical sensor output. This way, spiders and insects cannot fool the optical sensor.

Managing a network of precipitation samplers represents a formidable data management and quality control task. Network quality control operations are greatly simplified via TPC data management tools. Sampler and rain gauge history can be collected via telephone modems or via IrDA-equipped Palmä handheld devices that users physically carry to locations with Internet data connectivity back to the central network site.

TPC-3000 with lid closed

In addition to supporting connections to other data loggers and serial terminal devices, you can view data via the supplied Palm handheld device. Inexpensive Palmä devices are powerful, rugged and easy to transport. With their ample data storage and built in IrDA support, PalmOSä devices eliminate the need to bring a laptop and cables to remote collection sites. Palm devices also offer a compelling alternative to other, more expensive handheld devices such as Laptops, which tend to be more fragile.

Once the Palm handheld is synchronized with the Palm Desktop, data can be ingested into other TCP/IP-based databases. System errors such as jam conditions or power outages are logged to permit network level site audits and support online quality control. Periodic maintenance includes cleaning the precipitation sensor and checking the standby battery electrolyte level. The included TPC Manager software for the Palmä OS has the following capabilities:

Supports walk-up wireless data transfer to your Palm device via IrDA

Synchronizes with the Palm Desktop Software

Provides immediate graphical feedback¾ you can browse data immediately after collection

Detectable system failures are immediately apparent to permit on site repairs

The TPC Manager’s Instruments screen lists each instrument currently registered with it. You can then manage instruments and view their data. By selecting "Edit", you can also edit instrument/site meta data.

Notes can include site details, maintenance log information, operator names or other important site-specific data.

You use the Event viewer to see detected automation failure alerts, or precipitation start/stop events that represent normal operation. You can filter alerts only, and events have GMT/UTC date/times.

The Graph view gives you a high level visual snapshot of collected data. A graph view is convenient for browsing information, and for correlating vs. rain gauge data. By selecting Day or Week you can zoom the time scale to look at a region of interest.

The TPC-3000 was developed in partnership with the National Oceanic and Atmospheric Administration, and incorporates many features suggested by National Atmospheric Deposition Program (NADP) personnel. Problems such as splash and expandability were carefully considered and rectified. Common operational problems solved included lid freeze-down, motor and precipitation sensor failures, and poor sensitivity to precipitation under windy or very light precipitation conditions.