NIR Spectrometer Systems for Process Control

Polytec PAS spectrometers are the ideal solution for online NIR testing of chemicals or nutrients for process control. The transmission grating design and diode array detector technology enable the measurement sensitivity, speed, and stability that Polytec customers value.  

Contact or non-contact sensors independently connected to the spectrometer with long fiber optics allow the systems to be flexibly installed in many different situations.  An optional multiplexer enables up to 6 measurement points at a low cost per sensor.  

PAS spectrometers are available in multiple controllers with either a 110-240 VAC or 10-30 VDC actively stabilized power supply for flexible installation in manufacturing or outdoor mobile applications, like a truck, conveyor, grain harvester, etc. 


  • Uniform diffraction-limited spectral resolution, very low scattered light, high sensitivity, and long-term stability
  • Fast measuring times
  • Contact and non-contact sensors for testing solids 
  • Process Control software with any standard contol system interface including MODBUS, Ethernet/IP, Profibus, and others 
  • All software enables open access to data in text or other accessible format.  Free instrument control drivers. 

NIR Spectrometer for Process Monitoring

Image Credit: Polytec

NIR Spectrometers for Industrial Process Control

Polytec NIR Spectrometers for Industrial Process Control

Video Credit: Polytec

Different Models

PAS 1720/1721 and 1751

The compact diode array spectrometers (256 or 512 pixels) are fitted with TE cooling and cover a wavelength ranging from 850 nm to 1650 nm. They are either available in the 19″ housing (PAS 1720) or the ½ 19″ housing.

PAS 2120/2121

These diode array spectrometers (256 pixels) also have TE cooling and could be utilized in a wavelength ranging from 1100 nm to 2100 nm. The PSS 2120 is combined in the 19″ housing, while the PAS 2121 has been combined in the ½ 19″ housing.

Technical Data

Source: Polytec

Model Wavelength range Housing in inch Detector Resolution
PAS 1720 850 to 1650 nm 19 256 Pixel from < 6.4 nm
PAS 1721 850 to 1650 nm ½ 19 256 Pixel from < 6.4 nm
PAS 1751 850 to 1650 nm ½ 19 512 Pixel from < 4.0 nm
PAS 2120 1100 to 2100 nm 19 256 Pixel from < 7.9 nm
PAS 2121 1100 to 2100 nm ½ 19 256 Pixel from < 7.9 nm

NIR Spectrometer for Process Monitoring

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