Hi and welcome.
Sorry I can't answer about adding an EC-30 to your ERA 170X but I have the EC-30 on my RV and have attempted to set it up on battery state of charge. I say "attempted" because I seem to never have the settings quite right.
If you do some searching I think you'll find the EC-30 is not the easiest device to setup. I know there are posts on www.irv2.com
about setting up the shore power sensing function. It seems some RV Manufacturers install it incorrectly. I've never tested mine, and think I'll give it a try next week when the RV is home to load for a trip.
I suppose you've already seen the installation and operation instructions. But if not here's a link to the PDF.
Here's a video of a guy that installed one in his RV: