WP4 & WP4-T Dewpoint Meters
Measuring water potential using a pressure plate or filter paper is imprecise and can take several weeks. The WP4 and WP4-T measure water potential in less than 5 minutes from 0 to -300 MPa with a resolution of 0.1 MPa. Using the AOAC-approved Chilled Mirror Dewpoint Technique, the WP4 measures water potential by determining the relative humidity of the air above the sample in a closed chamber (at temperature equilibrium, relative humidity is a direct measurement of water potential). The instrument is easy to use and maintain, and calibration is simple.
WP4-T with Internal Temperature Control:
The WP4-T features internal temperature control. Water potential mesurements are temperature
sensitive: if the lab temperature fluctuates ±5°C, water potential readings can vary as
much as ±0.5 MPa. The WP4-T enables you to eliminate the effect of ambient temperature
fluctuations.
Other applications of internal temperature control:
- To study effects of temperature on water potential.
- Sample-to-sample comparison of water potential independent of temperature.
Features:
The WP4 is a bench-top enclosure with an integral sensor drawer. To initiate a reading, simply close
the sample drawer. You can transfer your soil suction data to a computer or printer with the included
serial RS232 interface cable. Additional features include:
- Easy-to-clean, durable one-piece sensor.
- Push-button calibration using performance verification standards.
- Continuous measurement mode (for time-dependent studies or samples with low water emission).
- Intelligent error messages to keep you informed of instrument performance.
Benefits:
- Unparalleled accuracy.
- Speed: 5 minutes per sample.
- 1 year warranty on parts and labor.
- Auto-ranging: Up to 50% faster speed at all soil suction levels.
- No tool maintenance: Thumb-screws secure lid and sensor plate.
Each WP4 and WP4-T is shipped with:
user manual, cleaning kit, 12 KCl verification standards, 100 sample cups and lids, an RS232 serial
cable, and a power cord.
| Specifications | |
| Operating Enviroment: 5 to 43°C (41 to 110°F) |
Interface Cable: Standard RS232 serial cable (included) |
| Temperature Control (WP4-T only): 15 to 40°C (±0.2°C) |
Weight: 3.2 kg (5.2 kg shipping weight) |
| Data Communications: RS232 compatible, 8 data bit ASCII code, 9600 baud, no parity, 1 stop bit |
Sensors: 1. Infrared temperature sensor 2. Chilled-mirror dewpoint sensor |
| Universal Power: 110 V to 220 V AC, 50/60 Hz |
Warranty: 1 year, parts and labor |
| Display: 20 x 2 alphanumeric dot-matrix LCD with backlighting. |
|
| Case Material: Powder-painted aluminum |
Range: 0 to -300 MPa |
| Sample Dish Capacity: 7 ml recommended (15 ml full) |
Accuracy: ±0.1 MPa from 0 to -10 MPa ±1% from -10 to -300 MPa |
| Read Time: ~5 minutes for most soil samples ~20 minutes for plant tissue samples |
Enclosure Size: 24.1 x 22.9 x 8.9 cm (9.5 x 9.0 x 3.5 in) |