High-Performance Multiplexer

More flexibility and efficiency for NIR process applications at several measurement points

Multiplexer FMX

Efficient Realization of NIR Process Applications with up to 16 Measurement Points Using Only One Spectrometer

Increasing demands on the flexibility of industrial production plants in the (petro-)chemical, pharmaceutical, food and beverage industries call for future-proof automation systems.

  • Processes are optimized to the maximum with the help of process analytical technology (PAT) and must be economical along the entire value chain.

  • This requires a flexible and cost-efficient integration of measuring interfaces at various points in the process, which continuously analyze and monitor the production.


The high performance  »Multiplexer FMX« enables process analytics with measuring interfaces at up to 16 different measuring points with only one spectrometer.

When does the multiplexer become profitable?

  • You want to implement a spectroscopic solution for at least two NIR measuring points !
  • You want to significantly reduce your investment costs per measuring point !
  • You want to avoid the acquisition & maintenance of several spectrometers !

Measurement of Liquids in Transmission or Transflection

With a focus on liquid measurement, the main application area of the Multiplexer FMX is online installations for measurements in transmission or transflectance. This way online measurements can be realized in different process steps and on several production lines with only one spectrometer.


The integration can be carried out efficiently and customer-specific

  • with different probes and measurement cells,
  • in different process steps
  • on several production lines
  • for a wide range of applications.

All Benefits at a Glance:

Reduction of investment costs per measuring point

High transmission & equally good performance             on all channels

Flexible at any     time expandable up to 16 measuring points

Reduction of Investment Costs per Measuring Point

The optical switching between different channels of the multiplexer makes it possible to use several measuring points with one instrument. This enables the user to forward measurement signals from several spectroscopic sample interfaces to a single process spectrometer.

Example with 3 measurement points without »Multiplexer FMX« 

Example with 3 measurement points with »Multiplexer FMX« 

The investment costs for the installation and connection of one measuring point are significantly reduced. Thus, up to 16 different probes and measurement cells can be installed in a space-saving, simple and economical way. Due to the efficient connection of several measuring points, the use of a multiplexer already pays off from two measuring points.

ROI (Return on Investment)

The following is an example of the investment costs with and without the use of a multiplexer depending on the number of measuring points. The implementation costs are always the same and constant in both cases.

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High Performance on all Channels

The »Multiplexer FMX«  gives you stable, precise and reproducible measurement values. This simplifies the method transfer to other measuring points in the production plant and reduces the workload. Overall, the multiplexer contributes significantly to process transparency and enables you to achieve optimum control.

High Transmission

The integrated high-quality optics with retroreflector always redirect the light beam optimally and thus ensures high transmission. This is a technical advantage compared to solutions with a prism.

High Precision and Reproducibility

The integrated stepper motor precisely selects any channel in less than one second. As opposed to solutions with piezo motors, high-quality optics are used to switch the channels and prevent frequency shifts. This high precision and repeatability of the switches lead overall to a high transmission and reproducibility of the optical signals.

Undisturbed signal transmission

The structural separation of adjacent channels prevents interference of the measurement signal by so-called crosstalk and ensures undistorted signals. This ensures interference-free signal transmission at full capacity.

Product features that prove convincing in use

  • Excellent channel synchronization between transmitting and receiving channels
  • Uniform illumination of all channels
  • Short switching time between different channels <1s
  • Low interfering signals: no fringing, no cross talk
  • No frequency shift between channels
  • High comparability of channels due to rotationally symmetric optics





Demand-Oriented Product Equipment and Subsequent Expansion

The equipment of the multiplexer can be adapted in a modular way according to your actual needs and can be extended flexibly as well as economically at any time. 


Two Differently Equipped Models: 10 or 16 Channels

The basic version is designed for a total of 10 channels and offers 3 pre-installed channels as preparation for connection to the measuring points. Additional channels are freely selectable during product choice in the configurator.

  • Basic version with 10 channels 
  • 3 channels preinstalled
  • All further channels flexibly expandable
  • Extended version with 16 channels
  • 3 channels preinstalled
  • All further channels flexibly expandable

The multiplexer is equipped by default with the feature bidirectional and can switch both transmitted and received signals simultaneously. An unidirectional model is also available.

Accessory Set for Easy Integration and Maintenance

You also benefit from an accessory set matched to the »Multiplexer FMX« , included in the scope of delivery by default.

The accessory set enables easy integration into the production line, supports maintenance and provides additional safety in the application.

Mounting Plate

With the help of a mounting plate with drawer extension, the installation of the FMX in a 19" rack is facilitated. The fiber optic cables can also be securely and easily attached here.

Strain Relief

A strain relief provides additional mechanical protection for the connected optical fibers.

USB-Converting Cable

With the USB converter cable, the FMX can be easily connected to a PC via a serial interface.

Software Module

A software module (SIMFMX01) for manual control via a PC is available free of charge on request. With the display and control function, test measurements and maintenance of individual measuring points for instance can be carried out easily and in a time-saving manner.

Good to Know!

  • Compatible with common process control systems (PCS)
  • Control of the measuring points can be made arbitrarily & not necessarily in a fixed sequence
  • Can be easily connected to a process spectrometer via SMA / FC-PC connections

Configure Individually Now!

In the accessory section of the Hellma Product Configurator, you can configure your individual multiplexer version according to your needs.

Optical Probes and Flow Cells Configurator

Hellma offers the largest selection of products worldwide and the highest level of expertise to support your online measurements from UV to IR. Find the right measuring interface quickly and easily or configure your individual immersion probe or measurement cell.

Product Pictures

Products of the brand:

Info Process Analytical Technology (EN)




Spectroscopic Online Monitoring of Complex Manufacturing Processes Illustrated by the Example of Polymerization (Application Note EN)


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