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Rechner Sensors

Celebrating 45 Years of Capacitive Sensors in North America

Rechner Sensors / applications / foodbev / Food and Beverage

Level Detection of Liquid Food Products

Download this application note as a PDF with connection diagrams: PDF


In many industrial applications vibrating rod-type level detectors are used. In some cases these devices cause problems as a result of the mechanical principle the sensor is based on. Vibrating rods (even though they are built tough) are prone to mechanical failure, or can give you false signals due to build up, or can creating a cavity in compressible solids. Powder from granular material often works its way into the bearing and creates false level indication. The KA0689 26-series sensor has no moving parts and no place for material to build-up which eliminates the risk of mechanical failure.

The 26 Series sensors are made with food safe PTFE and work with both liquids and solids. Versions for areas with a risk of dust and gas explosion are also available with AtEx and IECEx approvals.


Remove the old level switch and mount the new 26-series sensor. Modification to the mounting bracket may or may not be necessary. The sensor is connected to the Rechner Logic Controller with a standard M12 connector cable. The Logic controller needs to be supplied AC power (100-240VAC). The Logic controller provides 24VDC to the sensor and controls a relay output. The sensor can also be used without the logic controller to provide a transistor output. Once the sensor is mounted and wired the sensor needs to be adjusted.

After installation, a 'full adjustment' of the sensor is done in this order:

  1. Locate the sensitivity adjustment potentiometer on the sensor. The adjustment potentiometer is recessed and located under a plastic flap that is there to keep dust out.
  2. Fully immerse the sensor into the bulk material.
  3. Reset the sensor's sensitivity by turning the potentiometer counter-clockwise 20 full turns, or until the sensor no longer sees the product (whichever comes first).
  4. Adjust the sensor to the product to be detected by turning the potentiometer clockwise until the sensor detects the product.
  5. Add 1/4 turn for safety by turning the potentiometer a further 90 degrees clockwise.

Parts Required:

  • Sensor: KA0689
  • Relay Power Supply: NA7001
  • 5 Meter Cable: 0.25SQX4C