Refractometers are used as an efficient tool for measuring the concentration of various substances in a solution. They can be used in laboratories to measure the concentration of sampled materials or inline for real-time monitoring of the concentration of industrial liquids. PTR100 is an inline refractometer which directly connects to the main piping. Moreover, it can be used in both clear and opaque liquids. The head and sensor processing units of the device are separated and can be installed in different locations according to process designs. PTR100 is fully calibrated and also temperature-compensated. Measured signals are available in different units such as Brix or nD, and also, they can be sent to the central controllers such as PLCs or DCSs using analog 4-20 mA current signal or through Modbus RTU RS485 communication protocol.