Hi, I read in an instrumentation book that it is recommended to use a separate ground for each of:

1. Power supplies (SMPS 24V Primary Secondary voltages and 3.3,5,9,12 and 15V)
2. CANBus
3. Data signals etc

Can anyone explain how this would be implemented? When I design circuits I connect all grounds to the same point to avoid current loops but only use the power supply ground, I haven't used an SMPS Transformer yet but I heard each individual secondary supply needs one. .

I tried looking further into this but can't find the answers. Can anyone explain or recommend a good web source or book please?

 

Draw a block diagram for all your PCB, and label the power voltage, if the description are more clear then the answers will be closing to what you want.

SMPS was a power made by the switching square signal over 25Khz, a SMPS transformer is a parts of EE, and the transformer working over 25Khz, unless you want to design the power by yourself, otherwise you might want to buy a SMPS (A power supply), not a SMPS Transformer (a transformer).

 

Typically a star or single-point ground is used. Each of the circuit's ground is brought to a signal ground point, as you already said you do. The main thing to avoid is having any high ground currents go through sensitive parts of the circuit. Thus, for example, the power ground should connect to the output stage of a circuit, not the input stage. This article should help.