Valcom 27L Series

What is it?

The DS27L01 is a float-type level transmitter. A magnetic float moves along a guide tube and activates reed switches inside. The electronics convert these changes into a continuous output signal that represents the liquid level.

Where is it used?

It is used in industrial and marine environments for measuring the level of liquids in tanks. It works with almost any fluid because it does not depend on conductivity, viscosity, pressure, or tank geometry.

How does it work?

A float containing a magnet rises and falls with the liquid inside the tank. As it moves along the tube, it triggers reed switches positioned inside. The transmitter reads these switch activations and outputs a proportional 4–20 mA signal. Optional versions can also measure minimum/maximum levels or include a temperature sensor.

What problems does it solve?

It provides a simple and reliable method to measure liquid level without being affected by fluid properties. It offers precise, repeatable measurement, supports alarm functions, and allows internal components to be replaced without removing the unit or recalibrating.

Electrical/Output

Supply voltage (2-wire): 12 to 30 V DC
Supply voltage (3-wire): 16 to 26 V DC
Output signal (2-wire): 4 to 20 mA
Output signal (3-wire): 0 to 10 V DC (min. 30 mV) or 0 to 5 V DC (min. 30 mV)
Current consumption (3-wire): < 5 mA with load ≥ 10 kΩ
Load resistance (2-wire): R = (Supply voltage − 12 V) / 0.02 A

Measurement Range and Performance

Measuring range (liquid level): 0.6 to 10 m
Minimum fluid specific gravity: 0.5 kg/dm³
Accuracy: ± 5 mm (total, including hysteresis, non-linearity and repeatability)
Maximum process pressure: standard version 16 bar; special version up to 40 bar
Long-term stability: < 0.1% Full Scale (FS) per year

Environmental and Mechanical Conditions

Ambient temperature range: −40 to +85 °C
Storage temperature: −40 to +90 °C
Process temperature (standard housing): −40 to +85 °C; with finned body variant: up to 130 °C
Housing / protection: stainless steel (AISI 316).
- House diameter Ø 27 mm: protection class IP65.
- House diameter Ø 55 mm: protection class IP67.

Additional Features and Options

Float-with-reed-chain construction: the magnetic float moves inside the guide tube; reed switches inside the tube detect float position and electronics convert that to output signal.
Continuous level measurement output (4–20 mA), with linear indication independent of tank shape.
Optional on/off control version: using two floats for minimum/maximum level or overfill alarm (output 5–15 mA).
It is possible to replace the reed chain without removing the transmitter from the tank, and no recalibration is required.
Optional built-in temperature sensor (PT100) inside guide tube to measure local fluid temperature.
Approvals / Certifications: supports explosion-proof zones (ATEX), PED, EMC compliance.
Marine type approval (suitable for marine / shipboard use).

27L Series Datasheet

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