Barksdale USE3000 Tank Level Transmitter up to 3000 mm

A float-operated continuous level sensor for tanks up to 3 metres

The Barksdale USE3000 is a tank level sensor for continuous level indication up to 3000 mm. A float on a 13 x 1 mm stem moves along a resistor chain, giving a total resistance of 0 to 100 kOhm that is read directly or converted by the MU3L transducer in the KLS terminal box. The datasheet places it in the Barksdale tank level indicating systems, alongside the USE3200 (Ex approved) and the USE6000 and USE6200 versions for lengths up to 6000 mm.

The sensor is vertical, installed through the tank top with a G2 tank screw or a DIN flange, and is typically used for fuel, hydraulic oil, lube, coolant and water tanks where a float signal is needed at a remote indicator or controller.

Technical specifications

Materials, floats and electrical connections

Stem and mounting element are stainless steel (1.4571, 1.4404) or brass, with other materials on request. Three stainless steel floats are listed: VA44, a 44 mm oval for media density of at least 0.9 g per cubic centimetre and 25 bar; VA52, a 52 mm oval for 0.74 and 25 bar; and VA80, an 82 mm ball for 0.5 and 16 bar. Electrical connections are ST1 (DIN 43650 cube plug, 3-pin plus earth), PG (PG 13.5 cable gland with 1.5 m cable), KL6 (aluminium terminal box, 58 x 64 x 36 mm, 3 terminals) and KLS (aluminium terminal box 75 x 80 x 57 mm including the MU3L transducer). Protection is IP65 for ST1, KL6 and KLS and IP67 for PG. Wiring is 3-wire, up to 5000 mm depending on cable diameter.

Accuracy, temperature and ordering code

The standard R12 resistor screen is 12.7 mm (1/2 inch) with an accuracy of plus or minus 6.4 mm, about 0.2 percent at 3000 mm measuring length; an R08 fine screen is also shown. Supply is 8 to 35 V DC with the transducer or at most 24 V DC without it. Temperature range is -10 to 90 C, or -50 to 150 C for the HT version, which is only possible with the KL6 box or silicone cable. The datasheet order example is VA G2 KL6 VA52 R12 2000, meaning stainless steel, G2 tank screw, KL6 box, VA52 float, R12 screen and a 2000 mm measuring length LM. Options are DR slosh tube, Pt100 or thermo reed temperature measurement (PT100, TR), HT insulation and TM interfacial level indication.

How the resistor-chain principle works

Inside the stem of the USE3000 is a chain of resistors and reed contacts arranged at the screen pitch, 12.7 mm for the standard R12 version. A permanent magnet in the float closes the reed contact at its current height, so the resistance measured between the terminals changes in steps as the level rises or falls. Because the output is a simple resistance of 0 to 100 kOhm, it can be read by a resistance input on a controller or indicator, or converted to a standard signal by the MU3L transducer fitted in the KLS terminal box.

The step size defines the resolution: a finer R08 screen gives smaller steps than the standard R12. There is no moving electronics in the tank, which is why float-and-reed-chain sensors are widely used on fuel, lube and hydraulic tanks where a robust, simple level signal is preferred.

Selecting the right float

The float must have a density margin against the lightest liquid it will see, and the tank opening must be large enough for the float to pass through during installation. If the opening is small, the VA44 is usually the easiest to fit.

Choosing the connection and output

• ST1 cube plug – quick disconnection for maintenance, IP65.
• PG cable gland with 1.5 m cable – IP67, suited to wet locations or wash-down areas.
• KL6 terminal box – aluminium box for field wiring; required, together with silicone cable, for the HT high-temperature version.
• KLS terminal box with MU3L – when a converted signal is needed for a PLC, DCS or remote display instead of a raw resistance.

Applications in Oman and the GCC

Typical uses include diesel day tanks for standby generators, hydraulic power unit reservoirs, lube oil tanks on compressors and pumps, cooling water tanks and chemical dosing tanks in water treatment. Outdoor tanks in the region can see high surface temperatures in summer; the standard range of -10 to 90 °C covers most ambient conditions, and the HT version extends this where the liquid itself is hot. For storage of flammable liquids in classified areas, the USE3200 Ex version from the same family should be considered rather than the USE3000.

Maintenance tips

• Inspect the float for deposits or sludge build-up, especially in fuel tanks, as added weight changes the immersion depth.
• Fit the DR slosh tube option in tanks with strong turbulence or filling jets to stabilise the reading.
• Check cable glands and box covers to keep the IP rating, particularly after maintenance.
• Verify the output at empty and full levels during commissioning and record the values for later comparison.

Installation and what to confirm before ordering

The float immersion depth at density 1 is 36 plus or minus 2 mm for VA52, 35 plus or minus 2 mm for VA44 and 41 plus or minus 2 mm for VA80, and the overall length L0 is the measuring length plus the dead zones shown on the drawing (about LM + 110 mm for the G2 screw with VA52). Confirm the tank height, fluid density against the float minimum, working pressure, the output you need (resistance or the MU3L converted signal) and whether the tank is in a hazardous area, in which case the separate Ex version applies. The attached file is the two-page Barksdale tank level indicating systems datasheet. See more in level instrumentation; send the full code and tank data for a quotation.