Use the WP4 to measure water potential in 5 to 10 minutes. Range: 0 to -300 MPa with a resolution of 0.1 MPa.
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 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.
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).
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.
|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 labour|
|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 aluminium|
|Data Communications||RS232 compatible
8-data bit ASCII code
1 stop bit
|Display||20 x 2 alphanumeric dot-matrix LCD with backlighting|
|Interface Cable||Standard RS232 serial cable (included)|