On your emonPi, there’s a pushbutton. If you press that, do you see the display change? If so, cycle round that until you get the option to enable SSH.
If you can’t see that option, then you need to take the SD card out and write a file onto the card. The file name is ssh and it goes into the /boot directory. It doesn’t need to contain anything, it just needs to be there.
(See emonPi SSH disabled by default)
Once enabled - either way, you should be able to get in.