Thank you for the info.
I am actually working on the interfacing with Optris Pi so we can use it directly for regulation loop. It is quite easy, altough there is some bug that prevents from working.
I am waiting for Optris staff to help me with the solution.
Then everything will work with Raspberry Pi.
So we can use PCE-830, Voltcraft IR, GCM-300 geiger, Optris Pi. Everything with small and cheap embedded computer.
Normally you need few computers for this, but I really hate this way as it can be driven much better and more reliable for long time.