Hydac HNS 3226-2-0250-000 Magnetostrictive Level Switch

A float-based level switch with 1 % accuracy for hydraulic tanks

The Hydac HNS 3226-2-0250-000 (HYDAC part number 924254) combines a magnetostrictive float sensor with a four-digit display and two PNP switching outputs. The float rides on a stainless steel rod and the instrument reads the float position with a repeatability of 1 percent of full scale, a tighter figure than the capacitive ENS 3000. The 3226 version has no temperature sensor and uses a G3/4 A DIN 3852 male thread.

HYDAC lists fluid level monitoring of hydraulic tanks as the main use. In this code the probe length is 250 mm (9.84 inches), which gives a measuring range of about 7 inches.

Technical specifications

When to pick the HNS over the ENS

The magnetostrictive principle follows the float position directly, so the reading does not depend on fluid conductivity or permittivity. That makes the HNS more predictable if the oil type changes. Different floats are offered, including stainless steel versions for aggressive media, and probe lengths from 9.84 to 98.4 inches are listed in the datasheet. The trade-off is a heavier unit of about 1 kg compared with the compact capacitive switch.

Order code

HNS 3 X 2 X – X – XXXX – 000: the first digit selects the temperature sensor (2 is without), the next 2 is the G3/4 A thread, the plug digit 6 gives M12x1 four-pole (8 five-pole, P eight-pole), then the output digit (2 is two switching outputs, 3 one switching plus one analogue, 5 two switching plus analogue, 8 four switching plus two analogue), and 0250 the probe length in mm. Datasheet E 18.061.2.0 (USA edition).

Check that the float diameter passes through the tank port, because the float is fitted over the rod before the unit is screwed in, and ensure the float cannot be fouled by a baffle or suction line.

A magnetostrictive probe tracks the float position along its length, so the 250 mm figure fixes the sensing length. Choose the length with the tank height in mind, leaving room for the head and the float travel, and confirm the float density for your liquid.

Documents and quotation

The datasheet is attached. Send the tank depth, the fluid and the output you need. Related: our level instrumentation range.

How the HNS 3226-2-0250-000 works

Magnetostrictive measurement uses a waveguide wire running inside the stainless steel probe tube. The float carries a permanent magnet. The electronics send a short current pulse along the waveguide; where the pulse’s magnetic field meets the float magnet, a torsional wave is created that travels back to the sensor head. The time between the pulse and the returning wave is proportional to the distance to the float, so the HNS 3226-2-0250-000 knows the float position, and therefore the fluid level, very precisely. The result is displayed on the four-digit LED display and compared with the programmed switching points.

Since only the float position is measured, the reading is independent of the electrical properties of the fluid, and foam above the liquid has little effect as long as the float is not lifted. Repeatability and switching point accuracy are both ±1 % FS, specified for calm, non-turbulent fluid.

Functions and outputs

• Two independent PNP transistor switching outputs, programmable as N/O or N/C, each up to 1.2 A, with more than 100 million switching cycles.
• Switching and switch-back points adjustable independently, so the hysteresis can be matched to the tank volume and the pump cycle.
• Typical use of the two outputs: a minimum level alarm and a maximum level (overflow) alarm, or a pre-warning plus a shutdown signal.
• Reverse-polarity protection of the supply, excess voltage, override and short-circuit protection are provided.

On the M12×1 4-pole plug of the HNS 3X26-2, pin 1 is +UB, pin 2 SP2, pin 3 0 V and pin 4 SP1.

HNS 3226-2-0250-000 selection & ordering guide

The analogue output, where chosen, is 4 to 20 mA (load 500 Ω) or 0 to 10 V (load 1 kΩ) and needs an 18 to 35 V DC supply. The USA edition of the datasheet lists the modification number 400 for inch-based units; the 000 ending on this model is the standard version. Our team can help confirm the correct ordering code if you are replacing an existing unit.

Installation & maintenance

• Screw the unit into a G3/4 port on the tank cover with a suitable seal ring; the probe must hang vertically.
• Fit the float in the correct orientation before installation and check that it moves freely over the full measuring range.
• Keep the float away from return-line jets, suction strainers and baffles; use a splash guard from the HYDAC accessory range if the surface is turbulent.
• Maximum tank pressure is 43.5 psi (145 psi for less than one minute).
• During tank cleaning, remove deposits from the probe tube and float, and check that the float has not absorbed fluid or been damaged.

Typical applications in Oman & the GCC

The HNS 3000 is aimed primarily at fluid level monitoring of hydraulic tanks. Typical installations include hydraulic power units on industrial presses, steel and aluminium plant hydraulics, cooling lubricant tanks on machine tools, and power packs on mobile and marine equipment. With an operating range of –40 to +185 °F and fluid temperatures up to +248 °F, the switch suits hot reservoirs often found on plants across Oman and the GCC.

Why source from Seven Star LLC

Seven Star LLC supplies HYDAC level switches, accessories and connectors across Oman and the GCC. Request a quote for the HNS 3226-2-0250-000 and send your tank height and fluid details.