Column level indicators with temperature electrical probe
ELESA Original design
technical informations


Transparent polyamide based (PA-T) technopolymer. Highly resistant to shocks, solvents, oils with additives, aliphatic and aromatic hydrocarbons, petrol, naphtha, phosphoric esters. Avoid contact with alcohol or detergents containing alcohol.

Screw, nuts and washers

Zinc-plated steel.

Packing rings

NBR synthetic rubber O-Ring.

Temperature electrical probe

Zinc-plated steel screw with built-in probe. The probe is made out of a platinum resistor whose ohmic resistance changes according to the temperature.

Swivelling two-pin connector

With built-in cable gland and contact holder. Front or side output (right or left) including protection against water sprays (protection class IP 65 according to IEC 529 table) that can be increased during installation with the necessary adjustments. Flat NBR synthetic rubber packing rings.

Contrast screen

White lacquered aluminium. The housing, in the appropriate external rear slot, guarantees the best protection from direct contact with fluid, avoiding yellowing effect due to the prolonged action of the fluid at high temperatures.
It can be removed before installation to fit marks and words (for example MAX-MIN).


- When nuts can be fitted from the inside of the reservoir, by means of the supplied set screws and nuts.
- When nuts cannot be fitted from the inside of the reservoir and the walls are thick enough, by means of the supplied set screws, without nuts, by tapping the two holes in the reservoir walls.
- When nuts cannot be fitted from the inside of the reservoir and the walls are not thick enough, by means of the supplied set screws and the Fast Mounting Kit (for HCX.127).
To ensure the best sealing of the O-rings it is recommended to apply the maximum torque on the nuts as reported in the table and a roughness of the gasket application surface Ra = 3 µm.

Maximum continuous working temperature

90°C (with oil).

Special executions on request

- Level indicators for use with fluids containing alcohol or with hot water.
- Indicators with two red ball-shaped floats.

Features and performances

This column level indicator generates an analogic electric signal of the oil temperature.
Assembled using ultrasound welding to guarantee a perfect seal. Entirely in transparent material: maximum fluid level visibility even from side positions.

Technical data

In laboratory tests carried out with mineral oil for hydraulic systems type CB68 (according to ISO 3498) with gradually increasing pressure, at 23°C, the weld stood up as follows:
- HCX.127-STL 18 bar
- HCX.254-STL 12 bar
In any case we suggest to verify the suitability of the product under the actual working conditions. If you need to use the indicator with other oils or fluids and under different pressure and temperature conditions, please contact ELESA Technical Department or carry out tests in order to guarantee a proper use.

Two-pin connector assembly instructions

1. Remove the connector from the indicator by unscrewing the set screw placed in the bottom, take the contact holder out and loosen the cable gland.
2. Slip on the two-pole cable into the connector (standard connector) and connect the wires to the terminals nr. 1 and nr. 2 of the contact holder.
3. Assemble by pressing the contact holder into the connector in the required position.
4. Screw the connector to the indicator and then tighten the cable gland.

Functioning of the temperature electrical probe

The working principle of the temperature probe is to measure the variation of resistance of a platinum element: 100 ohm = 0°C, 138.4 ohm = 100°C.

The function between temperature (T) and resistance (R) is approximately linear over a small temperature range: for example, if you assume that it is linear over the 0° to 100°C range, the error at 50°C is 0.4°C. For precision measurement, it is necessary to linearise the resistance to give an accurate temperature. The most recent definition of the function between resistance and temperature is International Temperature Standard 90 (ITS-90). The function between resistance and temperature, obtained in laboratory tests, measuring directly the resistance value on the contacts is shown in the graph.

We suggest, anyway, to set the system in order to compensate both heat dissipation and cable resistance.
A 1°C temperature change will cause a 0.384 ohm change in resistance, so even a small error in measurement of the resistance (for example, the resistance of the wires leading to the sensor) can cause a large error in the measurement of the temperature.

Because of the low signal levels, it is important to keep any cables away from electric cables, motors, switchgear and other devices that may emit electrical noise. Using screened cable, with the screen grounded at one end, may help to reduce interference. When using long cables, it is necessary to check that the measuring equipment is able to handle the cable resistance.

Standard ElementsMain dimensionsWeight
Drilling and installation data
Descriptiond'-0.2f'±0.2Maximum tightening torque
Electric characteristicsTemperature probe
Power supplyDC
Maximum applicable voltage5 Vdc
Maximum rated capacity2 mA
Cable glandPg 7 (for cables in sheath with Ø 6 or 7 mm)
Conductors cross-sectionMax 1.5 mm2