Earthing?

[JAZZCNC]

Hi

Thanks for reply, excuse my ignorance what is a STAR?

Regards

Ray

Hi Ray,

Star means all AC Earths come from one point "Star point". This is very important so you don't introduce electrical noise into the system thru creating ground loops.
The signals coming and going from control software thru the parallel port to drives or sensing switchs like home switchs etc are very sensitive to electrical noise. This has the affect of tricking the motors, sensors etc into false moves or switching when shouldn't and cause real head scratching problems.

Mostly when people have missed steps or false e-stops etc it often turns out to be bad earthing practices. This is also why it's important to use sheilded cables for stepper motors and spindles ETC and correctly route back to the star earth point. (See quick pic showing)

NOW don't confuse AC Earth with the " - " or negative of the DC side of the system. While they ultimately all go back to the same Earth point they should be treat has separate and any DC negatives are best taken from a DC negative point. IE from the BOB Com or " - " pin or the " - " negative of the DC side of a PSU.
Often I'll run a single wire from the Main PSU DC negative to a distribution rail where I then pick up all the other DC negatives I need for drives ETC. . . . I do the same for DC positive as well.

All shielded cables should only be earthed at one end and that taken back to the main earth star point.

Hope the rough sketch helps.?