Whether logic and MDR are powered together or separately; the DC common (“-“) connections on all power supplies should be connected together. One of the power supplies should have its DC common connected to ground. Avoid connecting more than one power supply DC common to ground because this can lead to unintended grounding loops.

Separate groups of module each powered by single power supplies that are supplying both logic and motor power. Each supply has its DC commons tied together and connection to ground from a single point
Separate groups of modules each with their respective MDR power from separate supplies with a single common supply for each group’s logic power. Each supply has its DC commons tied together and connection to ground from a single point