WP4 Dewpoint Potentiameter
- Measurements:
- Applications:
Fast, Accurate Water Potential Measurements
Use the WP4 to measure water potential in 5 to 10 minutes. Range: 0 to -300 MPa with a resolution of 0.1 MPa.
Easy Operation
The WP4 is a bench-top instrument with a lexan sample drawer. To make a reading, set a cup in the chamber and close and latch the drawer.
Soil suction data can be stored internally or transferred to a computer or printer with the included serial RS232 interface cable.
Sample Size
Sample cups are 4 cm in diameter and 1 cm tall. They have a 15 ml capacity, but to protect the sensor from contamination we recommend that you fill them only half full.
No-Hassle Cleaning and Calibration
The WP4 sensor is easy to clean and durable. The instrument can be calibrated using saturated salt solutions (mix your own or order single-sample sized vials of standards on the accessories tab).
Chilled Mirror Dewpoint Technique
The WP4 measures water potential by determining the relative humidity of the air above a sample in a closed chamber (an AOAC-approved method). At temperature equilibrium, relative humidity is a direct measurement of water potential.
Water Potential Theory
Click this link to read more about the theory behind the water potential measurement made by the WP4.
Specifications
| Accuracy | ±0.1 MPa from 0 to -10 MPa 1% from -10 to -300 MPa |
|---|---|
| Range |
0 to -300 MPa |
| Measurement Time | ~5 minutes for most soil samples ~20 minutes for plant tissue samples |
| Temperature Control | 15 to 50°C (± 0.2°C) |
| Sensor Type | 1) Chilled-mirror dewpoint sensor 2) Infrared temperature sensor |
| Operating Environment | 5 to 43°C (41 to 110°F) |
| Universal Power | 5 to 43°C (41 to 110°F) |
| Warranty | 1 years, parts and labor |
| Sample Dish Capacity | 7 ml recommended (15 ml full) |
| Weight |
3.2 kg (5.2 kg shipping weight) |
| Dimensions | 24.1 x 22.9 x 8.9 cm (9.5 x 9.0 x 3.5 in) |
| Case Material | Powder-painted aluminum |
| Data Communications | RS232 compatible 8-data bit ASCII code 9600 baud no parity 1 stop bit |
| Display | 20 x 2 alphanumeric dot-matrix LCD with backlighting |
| Interface Cable | Standard RS232 serial cable (included) |
Comparisons
Accessories
Disposable Sample Cups
15 ml disposable sample cups come in lots of 100 or 150. Tight seal prevents changes in water activity as the sample is stored or comes to equilibrium.
Stainless Steel Sample Cup
Ideal for use with drying ovens. Set of 10.
Temperature Equilibrium Plate
Reduces read time by pre-equilibrating samples to instrument temperature. Also holds samples at a constant temperature.
Verification Standards
The WP-4 should be regularly checked against known water activity standards. These specific-molality salt solutions in single-use disposable vials make verification quick and easy.
Support
Material Safety Data Sheet
- MSDS 0.5m KCl
- MSDS 6.0m NaCl
- MSDS Activated Charcoal
- MSDS Decagon Cleaning Solution
- MSDS Distilled Water
- MSDS 8.57m LiCl
- MSDS 13.41m LiCl
- Material Safety Data Sheets
Application Notes
- Classification of Expansive Soils using the WP4C Dewpoint Water PotentaMeter
- Determining the -15 Bar (Permanent Wilt) Water Content of Soils with the WP4
- Effects of Sample Disturbance on Soil Water Potential Measurements
- Field Portability for the WP4C PotentiaMeter
- Generating a Soil Moistures Characteristic Using the WP4C
- Measurement of Leaf Water Potential using the WP4C
- Measuring Specific Surface of Soil with the WP4C
How-To Articles
- Classification of Expansive Soils using the WP4C Dewpoint Water PotentaMeter
- Determining the -15 Bar (Permanent Wilt) Water Content of Soils with the WP4
- Field Portability for the WP4C PotentiaMeter
- Generating a Soil Moistures Characteristic Using the WP4C
- Measurement of Leaf Water Potential using the WP4C
Manuals
Information Sheet
Request Support
Email: support@decagon.com
Phone: 800-755-2751 or
509-332-2756
Fax: 509-332-5158
Or send us an information request:
Education
Newsletters
- Water Potential Theory
- Geoenvironmental Engineering Newsletter-2007
- Soils News-1999
- Soils News-2004
- Soils News-2005
- Soils News-2006
Virtual Seminar
Video
Newsletter Articles
- January 11, 2007: Generating a Soil Moistures Characteristic Using the WP4C
- January 11, 2007: Measuring Specific Surface of Soil with the WP4C
- Newsletter-Measuring Soil Water Potential - One Hundred Years of Progress