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  1. Analytical sensors
  2. Conductivity sensor LDL

Using conductivity sensors to ensure quality and increase efficiency

Gruppenfoto LDL-Familie

The conductivity value indicates how well a material conducts electric current. In the water, food and beverage industries, as well as in other sectors, this value is used as an important measured parameter in quality assurance. It contributes, for example, to the optimisation of CIP processes or to the quality monitoring of ultrapure water. What is more, conductivity can also be used as an indicator for phase separation.


Product benefits

Compact design without additional evaluation unit
The compact LDL series combines evaluation unit and measuring element in one housing. This saves space in the control cabinet and significantly reduces wiring complexity. It also eliminates the need for an expensive data cable between the measuring element and the evaluation unit.
Standardised M12 connector instead of error-prone cable gland
The standardised M12 connector convinces with absolute ingress protection while also withstanding the severe conditions in hygienic environments. Moreover, errors when connecting the wires in the terminal chamber are ruled out.
Resistant design for hygienic and industrial environments
The fully welded stainless steel housing with protection class IP69K and the absence of seals, which can become porous over time, is convincing in hygienic applications. The sensor made of polypropylene, on the other hand, is always suitable when metallic sensors tend to corrode in the application. This may happen with salty ambient air, for example.
Flexible adapter options
The variety of adapters makes it easy to integrate the sensor via retrofit or in new installations. Thanks to the G 1/2" process connection, this already applies to small pipe diameters starting from DN25.
Plug & Work with IO-Link
The sensor is ready when you are: simply take the LDL out of the packaging and connect it. The conductivity in the medium is reliably determined right away.
Free factory certificate with every conductivity sensor
The factory certificate is included with all LDL conductivity sensors. It can be downloaded from our website free of charge with the serial number of the sensor.

System connection

Our conductivity sensors


The LDL100 is the right choice to identify process phases. The differentiation between media and resulting process phase identification plays a decisive role, especially in the food industry. Cleaning agents, rinsing water and products in the process pipes have different conductivity values and can therefore be easily and reliably detected thanks to the LDL100. This ensures unambiguous tracking at all times.


The LDL2xx conductivity sensors are the right solution for precise CIP monitoring or dosing of cleaning agents in parts cleaning. This is done with high precision over the entire measuring range starting from 100 µS/cm.


The LDL101 conductivity sensor is the right choice where the purity of water is crucial for product quality or process reliability. The sensor detects the conductivity of water from a value of 0.04 µs/cm. This makes it ideal for applications in water filtration where purified water of all levels is used. Possible applications here are water treatment, parts cleaning and critical supply systems (cooling water).


The LDL400 is the ideal choice for applications in which metallic sensors tend to corrode. These can be applications with brine or salty ambient air, for example. With a wide measuring range from 100 to 2,000,000 µS/cm, the sensor is suitable for numerous applications. Among other things, it can be used in almost every stage of water treatment. The sensor also meets the high requirements of the marine industry and is certified according to DNV EU RO Mutual Recognition Type Approval.

Overview of the areas of application

Selection guide: overview of conductivity sensors and their measuring ranges

Conductivity sensors in use

Learn first-hand from our customers about the variety of use cases for sensors and what added value they can bring in a wide range of applications.

Added value thanks to IO-Link

  • No measurement inaccuracies, such as occur with analogue transmission as a result of multiple digital and analogue conversion
  • Conductivity and temperature value: two values at one measuring point
    • fewer measuring points required
    • reduced initial cost
  • High measurement resolution without scaling
  • Quality monitoring with:
    • continuous display of the device status
    • operating hours histogram
    • internal memory for min. and max. conductivity/temperature values
  • Replacement devices can be detected and automatically configured by the IO-Link master

Did you know?

With a conventional analogue output, a large measuring range is scaled to 4..20 mA. As a result, the smallest changes in conductivity can often not be directly detected. This can lead to residual amounts of chemicals going undetected in rinse water or products, and in the worst case even result in product recalls. With IO-Link, however, the resolution of the conductivity value is always scaled to suit the used measuring range, so that the highest possible accuracy is guaranteed at all times.

Resolution comparison of IO-Link and analogue signals in µS/cm

Measuring range
IO-Link resolution Analogue PLC input card
LDL100 * LDL101 LDL200 LDL400
< 10 0.001 0.003
< 100 0.01 0.03
< 1,000 1 0.1 1 1 0.3
< 10,000 1 1 1 3
< 100,000 10 10 10 25
< 500,000 100 100 122
< 1,000,000 100 100 244
< 2,000,000 100 488

* LDL100 measuring range is limited to 15,000 µS/cm.

Installation instructions for conductivity sensors