I have a P12S driving 5V strips with a 5V power supply. I bought some floods this year that run at 12V and 24V. There will be a 24V power supply to drive the floods (with 24 to 12 buck converters). I want to use the DMX port on the P12S to control the floods. Do I need to have a common ground here? That is, the P12S is grounded to the 5V supply, and the floods would be grounded to the 24V supply, but if the P12S is providing DMX control, does that mean I need to ground the P12S with the 24V supply also? Or does the DMX cabling cover that? Thanks for any input.