The PAT-L is the newest member of the VIAVI PAT family of miniature process spectrometers. Its compact design and high performance make it ideal for use in industrial processes that require continuous monitoring. The NIR transmission design permits analysis of aqueous and nonaqueous liquids. The PAT-L is available in multiple configurations, specified on order, with a choice of probe material, optical path length, immersion depth, and process flange. As a member of the MicroNIR product family, it enables moving directly to production chemometric models and processes developed elsewhere. The PAT-L integrates readily with process equipment of all types and sizes, with the performance and stability to support truly efficient – and scalable – manufacturing.


  • All-in-one optical design for ease of installation and cleaning
  • Continuous liquid process monitoring in vessels, tanks and pipelines
  • Rapid acquisition time for real-time reaction monitoring and high flow liquid streams
  • Wide range of transmission path lengths for organic solvents and aqueous solutions
  • Full integration of light source and light pipe eliminates fiber optics
  • Broadly configurable to meet the needs of most processes
  • Optional cooling jacket for high temperature environments
  • USB-powered via hardwired cable
  • Includes MicroNIR Pro software, a complete data acquisition and chemometric modeling package

MicroNIR PAT-Lx Configurations

The MicroNIR PAT-Lx for hazardous locations consists of two main parts: The instrument head with probe and the barrier box, connected by a hardwired USB cable . The instrument head is identical to the MicroNIR PAT-L and consists of a spectrometer section and a probe section with integrated light pipe. The probe operates in transmission mode with an optical path length (gap) specified when purchased. The barrier box houses the interface electronics in a heavy, ruggedized cast aluminum enclosure. The barrier box has user-available ports for connections to Ethernet, 24 V DC power, and optional external trigger, using customer-supplied connections rated for hazardous locations. The barrier box comes with mounting brackets for attachment to process equipment.

Probe material*

  • Stainless steel 316L
  • Hastelloy C22

Optical path length (gap), mm*

  • 2, 3, 4, 5, or 10 mm

Maximum insertion depth*

  • 240, 440, 640, or 940 mm without flange
  • 100 to 900 mm with flange

Process connection*

  • Various EN, ASME, and other flanges available

Maximum temperature and pressure ratings

  • Up to 400°C and 40 bar
  • Dependent on material and flange


  • Class I Div. 2 Zone 1 and 2
  • Class II Div. 2 Zone 21 and 22 Class I
  • Groups C and D
  • Class II Groups E, F, and G

Please check the VIAVI MicroNIR PAT-L brochure.

To learn more please visit the official website.