I am learning on transmitters and input modules nowadays. But the usage of word 'ground' is confusing me. What does 'ground' mean there (earth or power supply common)?
If it is earth ground, why we need to do that? Just wiring to power supply common won't be enough? (Isn't it a real reference point of signal?) You can say it is to prevent having a floating signal, but what happens if power supply common is directly earth grounded? Also isn't it the nature of differential signal measuring to have a floating signal? If the input signal is differential and we make it earth grounded, won't it be like a single-ended signal?
If it should be earth grounded what happens if we don't wire it?
I also attached one example. What happens if I don't wire '-' of input signal to earth there?