Hi Martijn,
You are right in saying that the two main process variables are suction and discharge pressure, and the two corresponding controller outputs are compressor motor inverter frequency and Main EEV position. I’ve spent hours studying SNET-Pro2 output spreadsheets, pondering how the controller algorithm works, but without much success, though I can see that inverter frequency correlates quite well against water DT (i.e. LWT-RWT) - a linear fit over the full frequency range 20Hz to 60Hz has an R^2 greater than 0.95.
I suspect (but cannot prove) that the controller algorithm is predominantly using inverter frequency to achieve the desired (minimised) discharge pressure, whilst EEV position is predominantly used to achieve the desired (maximised) suction pressure.
I’m still puzzled by the power monitoring. There are possibly three relevant SNET outputs - Compressor Current1 (supposedly in degC!), OCT (which I believe stands for Outdoor (Unit) Current Transformer, but also shown as degC rather than A), and DC Link1 (i.e. post-rectification of the compressor inverter supply, also degC rather than V). But I have yet to figure out how to derive from any of these the number displayed on the remote monitor. Example: CompCurr = 3.1, OCT = 16, DCLink = 180, Outdoor power consumption (remote display) = 1.5kW. So A.V = 3.1 x 180 = 560W, not 1.5kW. I tried OCT/10 but this doesn’t always work either - see Struggling to get to grips with my Samsung controller post #44 ff. 