Electricity and Control August 2024

SENSORS + SWITCHES : PRODUCTS + SERVICES

Conductivity sensor for water treatment processes

ifm has introduced the LDL400 conductivity sensor, the polypropylene version of its proven LDL200 induc tive conductivity sensor. The material properties of the LDL400 conductivity sensor make it especially suitable for applications in which metallic sensors tend to corrode – where aggressive, acidic or alkaline media, such as cleaning agents, are used, or when in direct contact with salty ambient air. The measuring channel with an internal diameter of eight millimetres ensures optimum flow of the medium and minimises the risk of blockages. The LDL400 conductivity sensor can be used in al most any stage of the water treatment process. The conductivity of a medium is measured from 100 to 2 000 000 µS/cm and output as a temperature compensated value, in digital or analogue form. The wide measuring range means the sensor can be used in most water treatment applications. Furthermore, the percentage concentration of NaCl (sodium chloride) in ultrapure water can be accessed acyclically. Due to its material properties, the sensor can be used in the marine industry and is certified according to DNV EU RO Mutual Recognition Type Approval. This makes it an ideal choice for water treatment applications on ships. The compact design combines evaluation unit and sensor element in one housing. This saves space in the control cabinet and significantly reduces wiring complex ity. It also eliminates the need for expensive data cabling between the measuring element and the evaluation unit. A standardised M12 connector is used, instead of the usual error-prone cable gland. With ingress protection ratings of IP68 and IP69K, the M12 connector withstands severe operating conditions. Moulded plugs allow for quick connection and eliminate wiring errors as there is no terminal chamber. Water treatment – filtration and desalinisation The sensor measures the conductivity of the medium continuously in the range from 100 to 2 000 000 µS/cm. This means the LDL400 can be used universally in di verse water treatment applications and as an indicator of water quality. Fish farming – keeping the ecosystem in balance In fish farming, the sensitive ecosystems must be pre cisely controlled to enable successful and sustainable

breeding. If the system were to become unbalanced, this would result in the loss of the breeding stock and breed ing coming to a standstill. The salt concentration of the water, a relevant measured variable, can be determined reliably at any time with the LDL400 via the measured conductivity. Vertical farming – checking the concentration of minerals To optimise plant growth in vertical farming, it is impor tant to determine and adhere to the plants’ water require ments, and to check the concentration of minerals in the water. The LDL400 can be used to measure this concen tration and check whether it corresponds to the require ments. Thus it contributes to ensuring an optimum water supply for the plants. Digital communication via IO-Link IO-Link provides digital communication to the sensor, enabling: - Precise transmission of process values - Reduced wiring with decentralised IO-Link mas ters - Seamless digital information and values - Sensor data to be used via IIoT for MES and ERP - Best possible resolution across the entire measur ing range. With IO-Link, the resolution of the conductance is al ways scaled to suit the used measuring range, to ensure the highest possible accuracy. The EIO104 converter converts IO-Link process val ues quickly and easily into two 4...20 mA signals. This means IO-Link sensors can be connected easily to ex isting controllers with only analogue input cards. With analogue integration, the process value is output as a 4...20 mA signal. The LDL400 is supplied with 1 x ana logue output. Transparent processes Constant monitoring of conductivity and temperature al lows the user to keep an eye on the process at all times. The salt concentration of NaCl in ultrapure water can also be output acyclically. Easy set-up The conductivity sensor can be configured quickly and easily via IO-Link – either remotely or during the process. No additional transducer is required. In addition to displaying and logging the process val ues, various events can be recorded and simulated via IO-Link. If the device is to be replaced, the ‘backup & restore’ function automatically backs up and restores parameter sets via IO-Link, making it easier to replace the device.

Monitoring water filtration and desalination systems.

Optimising mineral content in water in vertical farming applications.

For more information visit: www.ifm.com

22 Electricity + Control AUGUST 2024