Aanderaa Water Level Recorder Model 7
The Water Level Recorder (WLR) model 7 is a self-contained, high precision instrument specifically designed for recording of ocean water levels through precise measurement of hydrostatic pressure. The WLR records pressure, temperature and conductivity (optional) at regular intervals, enabling precise variations in water level to be calculated. The pressure sensor consists of an oscillating quartz crystal which shifts frequency with the force applied to it. Temperature is measured by a Fenwall thermistor.
The data from the WLR7 are stored in a solid-state data storage unit (DSU) which can store up to 65,500 ten bit, PDC-4 coded words in a set of EEPROMS. Click the link for further details on the WLR7 .
Specifications
Pressure
| Oscillator Frequency | 36-40 kHz |
|---|---|
| Resolution | 0.001% of range |
| Repeatability | ± 0.01% of full scale |
| Integration | 40 s |
| Ranges available | 0 - 700 kPA (60 m) (standard)
0 - 3500 kPa (340 m) (standard) |
Temperature
The thermistor is a Fenwall GB32JM19
| Range | -3 °C to +35 °C |
|---|---|
| Accuracy | ± 0.1 °C |
| Resolution | 0.04 °C |
| Response Time | 30 s |
Conductivity (optional)
| Sensor Type | Conductivity Cell 3094 |
|---|---|
| Ranges | 0 - 77 mmho cm
-1
(standard)
0 - 42 mmho cm -1 (on request) |
| Accuracy | ± 0.25 mmho cm -1 |
| Resolution | 0.1% of range |
Further details can be found in the manufacturer's specification sheet .
