Back to the roots! Before obtaining PhD degree in the area of machine vision I designed automation systems. This year I "returned back to the roots" (for a shortwhile only) and designed a complete automation system controlling a MVR (mechanical vapour recompression) evaporator used for concentrating whey permeate. The PLC used controlling the evaporator is a Siemens S7 CPU 315-2 PN/DP with more than 200 inputs/outputs. OIU used for controlling the system is a WinCC v7.3.

 I have to confess I thought that tools for automation (programming etc.) would have developed more during the past years, but this does not seem to be the case. However, new tools have come out from Siemens, TIA, but it seems to "hog" all the resources of the computer that is running it. However, later versions should have gotten better.



The client was a Lithuanin dairy producer called Vilkyskiu Pienine.


My part consisted of choosing the used equipment and making complete set of electrical drawings (approx. 70 pages) for the system, programming both the PLC and the OIU, and startup of the system. Complete number of IO for the system is:

  • 100 digital inputs
  • 84 digital outputs
  • 32 analog inputs
  • 18 analog outputs


The system/process is controlled using a GUI programmed using Siemens's WinCC (ver. 7.3). All different parameters, recipe values etc. can be changed through the GUI.

 WinCC graphical user interface for controlling the process



When evaporator concentrates whey permeate, flow in/out are the following:

    • 13000kg/h at 18%
    • 585+kg/h at 40%


MVR evaporator

Jarno Ralli
Author: Jarno Ralli
Jarno Ralli is a computer vision scientist and a programmer.

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