Analogue Level Sensors | 4–20 mA Continuous Output

PROCESS SENSORS Level sensors (analogue)

Analogue level sensors provide a continuous 4–20 mA or 0–10 V output proportional to liquid or bulk solid level — used across water treatment, chemical storage, oil & gas, food processing, and hydraulic systems. Engineers choose them where real-time level monitoring, PLC integration, and process control are required, rather than simple point-level switching.

Other analogue level sensors

Weight & tape analog level sensors (yo-yo type)

Hydrostatic level sensors

Capacitive analog level sensors

Level sensor accessories

Magnetostrictive level sensors

Mechanical level monitoring sensors

Microwave analog level sensors

Ultrasonic analog level sensors

Latest products

FMI21-A1A1C1 Līmeņa sensors ; 4mA ~ 20mA Output Male 1 1/2"

Code: FMI21-A1A1C1

Supplier:

894.00 EUR (w/o VAT)

Capacitive level meter CLM-36N-20-G1-I-E900 4..20mA L=900mm Non-insulated rod electrode with reference tube for non-conductive liquids (oil, diesel, gasoline) Dinel

Code: CLM36N20G1IE900

Supplier:

440.00 EUR (w/o VAT)

Nivelco Pilotrek WPP1404M pulse radar llīmeņa sensors; 0,3-18m; 4...20mA + HART izeja; DN 40/ 1 1/2" BSP WPP1404M Nivelco

Code: WPP1404M

Supplier:

880.00 EUR (w/o VAT)

SGE-25 kabelis (1m.) paredzēts hidrostatiskajam sensoram AP-00071 Aplisens

Code: AP-00071

Supplier:

3.74 EUR (w/o VAT)

Konfigurējama sagatave SGE-25/10mH2O 4-20mA hidrostatiskajam sensoram līdz 10m + papildus kabelis pēc pieprasījuma AP-00068 Aplisens

Code: AP-00068

Supplier:

303.68 EUR (w/o VAT)

Līmeņa sensors šķidrumiem LFP1000-A4NMB LEVEL Switch, Continuous, 2 x PNP/NPN , 1 x 4..20mA/0..10V, rod probe length 1000mm, connector M12 x 1, 5-pin, power supply 24V, Process connection G 3/4 1057081 Sick

Code: 1057081

Supplier:

493.90 EUR (w/o VAT)

Nivopress NAW104 hidrosstatiskā līmeņa devēja notekūdeņu adapteris izgatavots no 1.4571 NAW1040M Nivelco

Code: NAW1040M

Supplier:

19.90 EUR (w/o VAT)

Multicont PRW18C1 Universālais programējamais kontrolieris PRW18C1M Nivelco

Code: PRW18C1M

Supplier:

786.85 EUR (w/o VAT)

SITRANS LR560 Radar level transmitter with flush lens antenna: continuous, no..., 7ML5440-0GB00-0AC2, Siemens

Code: 7ML5440-0GB00-0AC2

Supplier:

3329.00 EUR (w/o VAT)

Float switch, Pumptrol, open tank, NEMA 7/9, pedestal mounted, 2 NC DPST DB contacts, 9036DR31

Code: 9036DR31

Supplier:

248.10 EUR (w/o VAT)

Hydrostatic, ultrasonic, radar, capacitance and magnetostrictive types

Analogue level sensors output a continuous signal — typically 4–20 mA (2-wire loop-powered) or 0–10 V DC — scaled across the full measurement range. This category covers five main technologies:

Hydrostatic submersible transmitters — measure liquid head pressure at the base of a tank or open sump; well-suited for water, wastewater, and deep vessels
Ultrasonic transmitters — non-contact time-of-flight measurement; cost-effective for clean liquids, open channels, and stormwater applications
Radar and guided wave radar (GWR) — microwave-based, non-contact or probe-guided; preferred for vapour, foam, high temperature/pressure, or low-dielectric media such as hydrocarbons
Capacitance transmitters — probe measures dielectric change as medium rises; used for liquids, slurries, and bulk solids including food and pharmaceutical vessels
Magnetostrictive transmitters — float tracked via magnetostrictive wire; delivers high-resolution output for hydraulic reservoirs and fuel tank inventory

Key technical selection criteria

Output signal: 4–20 mA preferred for long cable runs and noise immunity; 0–10 V for short runs with compatible PLC inputs
Measurement range and blind zone: Ultrasonic sensors have a dead band (typically 100–500 mm) near the transducer — verify against maximum fill level
Process media: Liquid, slurry, bulk solid, foam, or vapour — each eliminates certain technologies
Dielectric constant (εr): Radar and capacitance sensors require minimum εr thresholds; critical for hydrocarbon and powder applications
Wetted materials: 316L SS for general use; PTFE or Hastelloy C for aggressive chemicals; hygienic connections for food/pharma
Process temperature and pressure: Standard sensors typically rated to 150°C; high-temperature radar extends to 400°C
IP rating: IP67 minimum for industrial use; IP68 for continuous submersion; IP69K for washdown environments
ATEX/IECEx: Required for Zone 0/1/2 (gas) or Zone 20/21/22 (dust) classified areas
HART protocol: Available on most 4–20 mA transmitters — enables remote diagnostics and configuration over existing wiring

Comparison overview

Type	Contact with media	Typical range	Best suited for
Hydrostatic	Yes	0–100 m	Water, wastewater, open sumps
Ultrasonic	No	0–15 m	Clean liquids, open channels
Radar / GWR	No / Probe	0–40 m	Chemicals, hydrocarbons, bulk solids
Capacitance	Yes	0–10 m	Liquids, slurries, food/pharma
Magnetostrictive	Float	0–5 m	Hydraulic oil, fuel tanks

When should I choose radar over ultrasonic for level measurement?

Choose radar when the application involves vapour, foam, high temperature or pressure, or low-dielectric media — conditions where ultrasonic signals attenuate or reflect unreliably. Ultrasonic is sufficient for clean liquids in moderate conditions.

Can I use a hydrostatic submersible sensor in an open pit or sump?

Yes — submersible hydrostatic transmitters are designed for this. Specify IP68 rating, a vented cable for atmospheric pressure reference, and sufficient cable length for the installation depth.

What does the blind zone on an ultrasonic level sensor mean in practice?

The blind zone (typically 100–500 mm below the transducer) cannot be measured. Ensure the maximum fill level of your tank stays below this zone, or select a sensor with a shorter specified dead band.

Do all 4–20 mA level transmitters support HART communication?

Not all — HART must be specified explicitly. It is standard on most process-grade transmitters from manufacturers such as Endress+Hauser, VEGA, and Rosemount, but not always included on lower-cost industrial sensors.