Originally shared by Marcus Wolschon
Got an answer from #Purelogic about the need to add separate power supplies for inputs on the even more expensive #PLCMB1 breakout board for my expensive #PLCME3P cnc controller.
(Had to go >4 axis due to my 5 axis CAM software development. So cheap USB boards where no longer cutting it,)
So you were suffering from supply noise?
No, using the +5V from the breakout board in a tool-height-probe (that is connected to the tool and thus the machine) would ruin the galvanic isolation.
I am suffering from strong Noise due to the spindle VFD and maybe the stepper motor power supply.
(I already moved the cooling water pump to it’s own power supply. This and the proper grounding helped a lot.)
Ground is a proper star configuration and the control board is isolated.
(Ethernet, optocoupled differential inputs, optocoupled outputs with galvanically isolated 5V for the external side of the breakout board. Spindle controlled via differential RS485 signal with no common ground)
So the noise does not affect operation. The separate 5V power supply for the tool height probe keeps that isolation intact.