NIR process sensor using modern diode array technology

The DA 7440 is a new type of NIR process sensor for over-belt placement. It uses advanced diode array technology to measure accurately even as recipes, ingredients or process conditions change.


NIR process sensors have been used in food and agricultural processing for many years, mainly forDA 7440 NIR process sensor measurement of moisture/oven volatiles. Up until now sensors have employed basic NIR filter technology, which is limited in analysis capabilities and needs frequent re-calibrations.

Diode array is an established, advanced NIR technology which measures accurately without re-calibrations even as raw materials or process conditions change. It collects all wavelengths simultaneously averaging multiple, full spectrum readings every second. By doing so it provides accurate measurement of complex parameters including moisture/oven volatiles, fat, sugars, seasonings and many more. This enables processors to reduce scrap, improve quality, and decrease time between product changeovers - all without laborious sampling and reference method testing.

Full-spectrum measurements

The reason behind the capabilities of a full-spectrum diode array instrument is that it uses all wavelengths of infrared light, whereas a filter instrument uses only a few wavelengths, typically 4-6. The difference is similar to the one between full color images and black & white images. With full colors you see all the nuances and fine details, many of which are lost in a black & white image.

The graph below shows a blue curve, which is the infrared information captured by a DA 7440. To a filter-based sensor most of this information is hidden though, as only a few wavelengths are measured. The narrow white bands represent the few wavelengths which are visible to a filter-based sensor. As can be seen, most of the information available only to a full-spectrum diode array instrument.

Industrial design

The DA 7440 is designed to be installed in food and industrial production areas and meets the particular demands of these environments. The stainless steel housing has high ingress protection (IP69k in DA 7440 SD version) and the cabling is kept to an absolute minimum, all in order to be easy to clean and maintain. To keep the sensor clean and free from contamination it can be equipped with an air-purge window.

System overview

The sensor is complemented by a central data processing and storage unit which communicates with SCADA and process control systems. The data unit also communicates with the optional at-line display which can be placed next to the sensor to allow operators to view results in numbers and charts in real-time.


Communication between the various system components is over Ethernet - wired or wireless. The user interface is web-based, meaning that authorized users can access real-time measurement information from a web-browser anywhere on the network. For example, whilst the operator is using the at-line display, the production manager can simultaneously view measurements in real time. The laboratory can independently add reference analysis results to the manual sampling report, allowing a quick and continues verification of sensor performance. This multi-user capability requires no additional software to be installed on any computer.

Process integration

By integrating the instrument in to the SCADA system, the operator can see the results in a familiar operating environment. Further, the results are available for automated controls and reporting through a central reporting system. The DA 7440 offers a range of communication options including:

  • OPC DA
  • Fieldbus including Profibus DP, Modbus, etc.
  • Ethernet TCP/IP based Modbus/TCP & PROFINET
  • Analogue outputs


The DA 7440 benefits many types of food and agricultural processors, such as:

  • Snack food - Moisture and fat with much better accuracy and stability than previously available NIR sensors. Also measure salinity and seasonings in real-time to verify additions. Read more
  • Other foods - Potato products, meat, cookies and many other foods can be measured for moisture, fat and more with excellent accuracy. Read more
  • Wood based panels and composite boards - Real-time measurement of moisture, formaldehyde emission and resin load among other parameters. Read more
  • Tobacco - Oven volatiles / moisture without any re-calibration between batches. DA 7440 also measures nicotine, sugars, nitrates, ammonia and more. Read more