4-20mA water level transmitters using two-wire loop power. Ideal for wells, tanks, rivers & reservoirs with excellent noise immunity & long cable runs. Designed for reliable integration with PLCs & SCADA in water management applications.
Water level transmitters equipped with a 4-20mA current loop output provide a dependable solution for integrating level measurements into industrial control and monitoring systems. These devices commonly utilize submersible hydrostatic pressure sensors and feature a two-wire design that simplifies installation by transmitting power and signal over the same pair of wires, offering excellent noise immunity crucial for long-distance transmission from locations like boreholes, rivers, reservoirs, and storage tanks. Understanding the specific design features, such as vented gauge pressure reference and material compatibility, is key to selecting the appropriate transmitter for reliable performance in diverse water level applications.
Underground rain water storage tank level sensor and readout for 2 metre depth - Water level indicator for a 2 metre deep rain water storage tank located underground. 
3m range 4-20mA output submersible hot water tank level sensor - This submersible level sensor is suitable for use in hot water tanks. It features a 4-20mA output, 0-3m measurement range, and high-temperature resistance up to 125°C (257°F).
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- Borewell water level sensor for 100m water height - Low cost solution to measuring the water level in a borewell with a water height of as much as 100 metres above the submerged sensor
- 200m deep well pump water level sensor, switch & display - Protect your deep well pump with thhis submersible level transmitter and wall mounted indicator and alarm. This system provides reliable water level monitoring and pump protection at depths of up to 200 meters.
- Dairy wash water tank submersible level sensor for temperature up to 100C and 2m high tank - Monitor wash water levels in high-temperature dairy applications with the LMK382 submersible level sensor, featuring 125°C temperature rating and durable construction.
- Storm surge protected low range submersible river level transmitter - This submersible level transmitter offers accurate low range water level monitoring with high overpressure resistance for storm surge protection in rivers
- Cooling tower basin water level transmitter - Ensure efficient cooling tower operation with the LMK382 submersible level transmitter. Its low-range measurement capabilities and robust design make it ideal for monitoring basin water levels, preventing pump damage, and optimizing water usage.
- High temperature mini sewage tank level sensor - Submersible level sensor for low-range sewage applications in small, high-temperature wastewater tanks.
LMK307 Submersible Waste Water Level Sensor
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- Dock bridge tidal flap submersible level transmitter with sea water compatibility - Marine bronze submersible level transmitter for reliable depth measurement in dock bridge applications with tidal flaps.
- Yacht diesel fuel and water level sensor for non-uniform shaped marine tanks - Submersible level sensors for irregularly shaped fresh water, grey water, black water, and fuel oil tanks on a classic sailing yacht.
- Surface water hydrostatic level sensor for shallow stream - Submersible hydrostatic level sensor and a vented terminal box with surge protection provide an accurate and robust solution for monitoring water levels in shallow streams.
- Remote water tank level monitoring via GSM mobile network - Monitor water levels in multiple tanks remotely using submersible sensors and GSM technology. Configure alarms for high/low levels and receive alerts via SMS or email.
- Rainwater harvesting depth sensor for 1 metre deep tank - Affordable and reliable depth sensor for rainwater harvesting tanks. Submersible design, 316L stainless steel, ideal for underground installations.
- 40 ftH2O Hydroelectric plant tailwater elevation & temperature sensor - Monitor tailwater elevation and temperature in hydroelectric power plants with the IMSTL submersible sensor. Dual 4-20mA output, 0-40 ftH2O level range, -14 to +122°F temperature range.
Find out more about Water Level Transmitters with 4-20mA Output to determine which product options and capabilities will best meet your application requirements.
Water level transmitters utilising the industry-standard 4 to 20 milliamp (4-20mA) current loop output offer a robust and reliable method for level measurement in various water-based applications. This two-wire configuration is particularly advantageous, allowing both the power required to operate the transmitter and the analogue level signal to be carried over the same pair of conductors. This significantly simplifies wiring installation and reduces costs, especially over the long cable runs often encountered in borehole, reservoir, or extensive facility monitoring.
The inherent nature of the 4-20mA signal provides excellent noise immunity compared to voltage signals, making it ideal for environments with potential electromagnetic interference often found in industrial settings or near pumps and motors. The ‘live zero’ represented by the 4mA signal allows monitoring systems (like PLCs, SCADA, or dedicated controllers) to easily distinguish between a genuine zero-level reading (4mA) and a fault condition, such as a broken wire or transmitter failure (which would result in 0mA).
These transmitters typically employ a submersible hydrostatic pressure sensor design. The sensor, housed within a rugged, sealed enclosure (often stainless steel grades like 316L for corrosion resistance), measures the pressure exerted by the column of water directly above it. This pressure reading is directly proportional to the water level. Accurate measurement relies on referencing the hydrostatic pressure to the local atmospheric pressure; this is achieved using a vented cable that incorporates a small breathing tube running alongside the electrical conductors, terminating in a protected, breathable location, usually at the instrumentation end. This vented gauge pressure measurement automatically compensates for barometric pressure fluctuations, ensuring true level readings.
Specific construction details are crucial depending on the application. For instance, monitoring levels in deep groundwater wells or boreholes necessitates transmitters with durable, abrasion-resistant cable jacketing (like PUR) and potentially narrower body diameters. Measuring levels in potable water storage tanks requires materials certified for drinking water contact (e.g., specific stainless steel grades, PE or FEP cables). River and reservoir level monitoring often demands robust designs capable of handling potential debris, sediment, and outdoor environmental exposure, typically requiring a high IP rating like IP68 for continuous submersion.
Integration into process control systems is straightforward due to the widespread compatibility of the 4-20mA signal. These transmitters are commonly connected to input modules on PLCs, dedicated digital panel meters for local display, data loggers for environmental monitoring, or telemetry systems for remote water resource management. The signal can represent the full calibrated range of the transmitter, allowing precise tracking of water levels within tanks for process control, monitoring resources in reservoirs for water management, or triggering alarms in flood monitoring systems. For applications in hazardous areas, such as certain wastewater tanks or industrial sumps, intrinsically safe (Ex ia) versions are available which limit the electrical energy to prevent ignition in potentially explosive atmospheres.
Product Help
Specifying water level transmitter with 4-20mA output requirements
Some questions to ask when defining the product requirements for a water level transmitter with 4-20mA output.
Installation type
How do you want to install the water level transmitter, will it be mounted to the outside of a water tank, lowered inside a water tank, or suspended from a platform above the water surface?
Water type
What kind of water will you be measuring, freshwater, seawater, drinking water, chlorinated water or wastewater?
Level range
What range of water level in metres or feet do you need to measure over?
If measuring a water tank, is the tank air tight or vented to outside air pressure?
Accuracy
How accurate does the water level measurement need to be?
Will it be used to determine the quantity of water, or to protect from overfill or underfill?
Electrical connection
Do you have a preference on what type of electrical connector and 4-20mA signal cable to use?
Will the water level transmitter be exposed to an indoor or outdoor environment?
Could the water level transmitter be temporarily flooded or will it be permanent submerged?
If a cable is required, how long does it need to be to connect to the water level measurement instrumentation?
Process connection
If the water level transmitter is going to be external to a tank, how do you intend to mount the sensor if it is going to be fitted to the outside of a tank, what type and size of thread or flange?
Temperature measurement
Would you like to measure the water temperature as well with a separate 4-20mA signal from the same transmitter?
Checklist for water level transmitter with 4-20mA output requirements
Define your water level transmitter with 4-20mA output requirements using this checklist:
- Installation type?
- Water type?
- Level range?
- Accuracy?
- Electrical connection?
- Process connection?
- Temperature measurement?