Modular design and ground splitting

[RawCode]

Hello everyone.
I need some advice.

I want to build a mixed-signal circuit, and I'm thinking to use a modular design approach, i.e., having different PCBs that perform different things, interconnected between them via cables.
This system should have a digital board where the microcontroller, ADCs, DACs, display and some buttons are located, and several analog boards (say 2) where signal processing is involved.
I would like a modular design for this project because if there is a need for a change in one portion of the circuit, I have only to swap the old PCB with the new one instead of having to redesign the whole PCB.

I studied a bit about EMI and related stuff and I also watched the recent videos of Robert Feranec about this topic.
In particular, in a video where he talked about ground in PCBs, its cohost, Rick Hartley, said that splitting grounds between analog and digital portion of the circuit can be dangerous and usually a potential source of EMI problems.

Now, considering that I'm not a very experienced engineer in this topic, how should I arrange this modular design to minimize this sort of problem?
Is the modular approach a bad idea?

Thanks

[thm_w]

Its a good idea if you are looking to reuse any portion of your project.
Its quite common to have a display board with buttons, micro, LCD, etc. on it.

Just be aware what you are transmitting and whats coming back, eg having high speed digital going to the analog board and a low level analog signal coming back is not going to be ideal.
But if you just have digital signals going to the analog board, and the board is well laid out, most likely there will be no issues.

You can post your schematic or block diagram here, or in the projects forum, so its more clear what you are trying to do.

[penfold]

In agreement with the post above.

If you plan to attach the modules to some metalwork, chassis, metal box, etc, just be wary of connecting the screw holes in the PCB to 0V, least maybe not directly - leaving an 0805 footprint available for solder-blob (or 0-ohm link if feeling fancy), Y-capacitor or just disconnected can give you a quick opportunity to solve a possible problem that may or not exist quite cheaply.