Conductivity sensors

What is electrical conductivity?

Electrical conductivity is the ability of a medium to conduct electric current. It is expressed in the unit of measurement S/m (Siemens per meter). The higher the conductivity, the more free ions in the form of bases, salts and acids are present in the liquid. A further factor influencing conductivity is the temperature of the medium. As the temperature increases, the mobility of the ions decreases, which in turn increases the conductance.

So-called conductivity sensors make use of this property.

What function do conductivity sensors have?

Conductivity sensors usually consist of two metal plates that determine the electrical capacity of a substance by contact with the medium.

These sensors were designed especially for the food industry, where you will be responsible for the following tasks, for example:

• Determination of mixing ratios
• Phase separation detection
• Detection of the cleaning liquid concentration
• Rinse water monitoring for residues
• Issue of the product release

In order to detect a contaminated system or product residues as well as cleaning agents in the rinse water, it is not necessarily required to know the conductivity of a medium. Instead, one sensor can be attached to the inlet and another sensor to the outlet to compare both values. In this way it is possible to check whether the initial conductivity value has remained the same. If this is not the case, it can be concluded that another substance has been added.

Compact conductivity sensors from ifm at Automation24: Which one is right for you?

In the category Sensor systems at Automation24 you will find two innovative conductivity sensors of the LDL family from the quality manufacturer ifm.

In contrast to the models currently available on the market, the process sensors have a small and compact design with standard M12 connectors and are easy to operate. A separate evaluation unit is not required.

Which conductivity sensor is suitable for your needs?

If you do not want to detect mixing ratios and are looking for a sensor whose accuracy is suitable for most phase separation measurements, then the price-saving conductive conductivity sensor LDL100 meets your requirements. On the other hand, you should choose the LDL200 inductive conductivity sensor if, for example, you want to meet more stringent requirements in CIP applications. This includes the detection of cleaning agents and rinse water residues or the determination of chemical concentrations and the salt content of a substance.

Both conductivity sensors are equipped with IO-Link interface, which offers you further advantages such as continuous monitoring of the sensor performance, maintaining resolution and accuracy over the entire measuring range, planning of maintenance intervals and the resulting reduction of downtimes. You can also find suitable IO-Link components in the online shop with corresponding IO-Link masters and IO-Link programming tools.