Hello, the MIO module is grounded to yellow/green earth through the wall outlet. What do you mean with the digital ground?

Hello!
I am using my MIO extension for my RevPi Connect S
I have one analog input which i have put 5 volts on. The value in the computer is around 5000 then.
However, when i put a high 24v dc on digital input 1 in the X2 connector, the analog value becomes 10744. Eventhough only 5 volt is on the ...