Indigo520 for process refractometers

Data logging, wash control, trends, settings and measurement parameters

Vaisala Polaris combined with Indigo520 offers compelling features for all users and are a standard power couple for applications and installation positions with prism wash system. 

Access data and different features through the Indigo520, including data logging, wash control, settings, measurement parameters and Indigo service updates to Indigo520. 

The Indigo520 for process refractometers offers versatile system connectivity by two selected analog or digital inputs for process refractometers and other Indigo compatible probes, and four configurable analog outputs to alarm relays, and ModBus TCP/IP digital protocol.   

Key benefits

Direct access:

Direct, easy to use touch screen interface

Prism wash control:

Including wash sequence control, intelligent wash programs, and more. 

Unique in the world, Vaisala offers a retractable refractometer with a wash nozzle for green liquor.
Download application note: Kraft (Sulfate) pulp: causticizing  

Data logging:

Log 14 days of measurement data, in rapid intervals. Easy data download to Excel from web browser interface.

Concentration curve management

Easily switch between different concentration curve and field adjustment options to measure different products or process liquids on the same pipeline. 

All Indigo family instruments at your fingertips:

Connect up to two Indigo family products, for example process refractometers, temperature, humidity, CO2 or vaporized hydrogen peroxide H2O2,.

Select the instruments most appropriate for your process and enjoy the smooth operations.

Software updates for the Indigo520 transmitter

Easily update the software of Indigo520 for process refractometers with the Vaisala Insight PC Software.  

Accessories: spatter guard

The Indigo520 for process refractometers comes with a spatter guard option for extra protection in the outdoors or heavy industry use, or when conditions are otherwise harsh. 

For pulp and paper, chemical, petrochemical and oil & gas industry, and harsh conditions. 


Looking for other measurement parameters with Indigo500 series?

For humidity, dew point, carbon dioxide CO2, vaporized hydrogen peroxide (H2O2), moisture in oil or barometric pressure visit Indigo500 product family page.

Indigo500 product family

Product Resources


All you need to know about liquid concentration and density measurements

Processing industries often handle liquids which need to be measured for product quality assurance. For comprehensive quality control, analysis of the liquid concentration is needed at different steps of the manufacturing process.



Measuring Real-Time TTA/Density of Green Liquor in Pulp Mill Causticizing with Process Refractometers

In this webinar you will learn about different methods to measure and control Green Liquor TTA/density in the causticizing process. 

Register to watch


Advantages of real-time dissolved solids content (TDS) measurement in fiber suspensions + implementation in individual BSW process steps and upper level process control

Experts will present advantages of real time dissolved solids measurement on specific focus points of the fiberline, as well as an optimization practice of the entire brown stock washing based on these unique measurement devices. 

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Brown stock washing optimization

Did you know that Total Dissolved Solids (TDS) is the only measurement that accounts for both inorganics and organics? Learn about this measurement parameter for Brown Stock Washing.



Real-life use cases on control practices and impacts before and after TDS technology implementation in brown stock washing

The focus is on how mills have identified bottlenecks and improved economics using Optimized Dilution Factor (DF) functionality. 

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Importance of brown stock washing and digester dissolved solids optimization for pulp mill efficiency

In an optimal case brown stock washing removes as much dissolved solids as possible while using the lowest amount of wash liquor or water.

Register to watch

Vaisala Polaris process refractometers

Go to Vaisala Polaris product family page

Vaisala Polaris