Capacitive Level Sensor for High Temperatures and Hot Melts

The LEVEL-CAP sensor is a level sensor for liquid, granular or powdery materials capable of measuring under high temperature conditions (up to 200°C).

It can be used with granules, powders or liquids, whether electrically conductive (e.g. water) or with insulating materials such as oils or hot-melt adhesives.

The LEVEL-CAP sensor consists of 2 parts:

CAP-SENSOR level probe to be placed on the tank of the product to be measured

CAP-LOGIC logic board which manages the signal coming from the CAP-SENSOR and provides digital (relay with potential-free contact), analogue (selectable in 0-10V or 0-20mA mode) or serial (used by the Easy-charge adhesive granule loader) outputs.

The CAP-SENSOR detects the level by measuring the capacitance between the sensitive electrode and the electrode used for cooling:

– In case of granules, powder or electrically insulating liquids, the reference electrode can be the wall of the tank where the CAP-SENSOR is installed (in this case the tank must be made of metallic or electrically conductive material; in case of non-conductive tanks, a metallic reference electrode must be placed a few cm away from the CAP-SENSOR electrode).

– In case of electrically conductive granules, powders or liquids, the material whose level is to be controlled acts as the reference electrode, provided that electrical contact between the CAP-SENSOR reference and the material itself is guaranteed. In this case it is necessary to provide the PTFE insulator for CAP-SENSOR code LEX-xxCMPT (where xx is the length of the sensor expressed in cm), to prevent the sensor from being short-circuited by the material itself, which would prevent it from working properly.

Microprocessor technology used by the LEVEL-CAP makes it extremely easy to program, which is done by self-acquiring the minimum (and if required maximum) levels.

To complete the parameters to be programmed, there is also hysteresis, which makes it possible to establish the amplitude of the level variation necessary to make the digital output (minimum level alarm relay) switch and to inform the Easy-charge charger of the need to recharge the tank.


Two types of level probes are available, both working with the same CAP-LOGIC logic board.

The CAP- SENSOR/125 has an electrode with a standard length of 125 mm, fully PTFE insulated for use with electrically conductive substances.

The CAP-SENSOR/EX consists of an 80 mm long main body.

The length of the electrode can be customised thanks to the innovative modular system consisting of extensions of 100 mm each: multiple lengths of 100 mm can therefore be obtained.

However, sensors with custom lengths and PTFE electrode insulation for use with electrically conductive substances are also available on request.

The LEVEL-CAP is easy to interface and integrate with existing systems, thanks to the presence on the CAP-LOGIC board of numerous outputs for various requirements:

  • Low level output with potential-free NC/NO relay
  • 0-10V / 0-20mA analogue output with level proportional parameters
  • Current-loop serial output for interfacing to special systems (e.g. EASY-CHARGE loader)

The CAP-LOGIC conditioning board is available in the following models:

  • CAP-LOGIC/EC: board equipped with direct output to the Easy-charge adhesive granule loader. This output is also present in the other models
  • CAP-LOGIC/xx/RL: card provided of relay output with NC/NO potential free contact. xx indicates the card power supply voltage (24Vdc or 230Vac).
  • CAP-LOGIC/xx/RL-AN: card provided with relay output with potential free NC/NO contact and analogical output. xx indicates the card power supply voltage (24Vdc or 230Vac)

LEVEL-CAP is also available in the version that can be combined with the EASY-CHARGE adhesive granule loader (cod. LEVEL-CAP/ECR) with the logic board housed in a circular plastic container equipped with a charge button and screen-printed panel as shown in the figure to the side.

This version has been specially designed to be installed directly on the charging hopper, making it compact and easy to install.

An alternative to the LEVEL-CAP/ECR version is the LEVEL-CAP/EC model, which is enclosed in a rectangular plastic container with a charge button and a screen-printed panel as shown in the figure opposite.

LEVEL-CAP/EC is prepared for installation on the granule transfer pipe by means of plastic clamps.

This version is only supplied for installations where it is impossible to install the LEVEL-CAP/ECR model for reasons of height.

LEVEL-CAP can be parameterised using the CAP-SETUP software, available from Emmeci Elettronica, and the serial connection cable CBL-LEVELCAP, which allows adjustment of the output switching times, the degree of measurement/speed accuracy, the minimum and maximum values of the analogue output and also allows testing of the sensor operation.