Global Water's WL400 Water Level Sensor provides highly accurate water level measurement for a wide variety of applications, including those in severe environments. The submersible pressure transducers have a dynamic temperature compensation system, enabling high accuracy measurements over a wide temperature range. The water level sensor is easily adapted to all dataloggers, telemetry, monitoring equipment, and displays.
Each of the water level sensors consist of a solid state submersible pressure transducer encapsulated in a stainless steel 3/4'' diameter housing. The water level sensor has a molded-on waterproof cable and a two-wire 4-20 mA high level output for connection to a monitoring device. A 25' cable is standard, and optional cable lengths are available up to 500'.
The Water Level Sensor's submersible pressure transducer is fully encapsulated with marine-grade epoxy so that moisture can never leak in or work its way down the vent tube to cause drift or level sensor failure (as is the case with other pressure sensors). The water level sensor uses a unique, highly flexible silicon diaphragm to interface between water and the sensing element. This silicon diaphragm protects the water level sensor's electronics from moisture and provides each sensor with exceptional linearity and very low hysteresis. The design of the submersible pressure transducers eliminates the issues associated with metal foil diaphragms, which tend to crinkle and stretch out over time causing drift, linearity, and hysteresis problems. The water level sensor is also protected by a stainless steel micro-screen cap, which makes fouling with silt, mud, or sludge virtually impossible.
Pressure transducer level ranges of 0-3', 0-15', 0-30', 0-60', 0-120' and 0-250' are available. The 0-3' low-level range is ideal for measuring shallow flows or small water level changes like those encountered in sewers, storm drains, weirs, and flumes. The 0-3' water monitoring sensor accurately measures small changes in water, even when the water's depth is only a few inches deep. Other metal foil-type water level sensors typically have serious problems at low-level ranges because of sensor crinkling, stretching, and drifting.
Each submersible pressure transducer has a two-wire 4-20 mA output signal that is linear with water depth. From 10 to 36 VDC is required to operate the water level sensor, so the level sensors can be operated from common 12 VDC battery systems. The 4-20 mA signal can run up to 3,000' from the submersible pressure transducer to the logging device. Common twisted pair or electrical extension cord wire may be spliced to the vented cable once the cable is out of the water. The 4-20 mA signal may be converted to 0.5 to 2.5 VDC by dropping the current signal across a 125 ohm resistor.