[Al_The_Man]

I have always preferred to connect all commons to earth ground where possible, and so far have not seen a problem, and also ensure the the machine has equi-potential bonding, IOW make sure that there is no possibility of ground loops.
Al.

[dsnellen]

Everything pretty much works except for a weird limit switch issue. I use hall effect switches. On the Y axis, the sensor is mounted so it moves over the magnets. One magnet is used for Y Home and Y++, and another magnet for the Y--. For some reason, if the Y-- is set on, I get switch activation at random intervals. Usually it is so often I cannot do anything. Simply disabling Y-- makes the problem go away for the most part. Its a magnet about 48" from Home & Y++. The debounce is set to 5500. The Index Debouce is set to 10, but I don't know why.

And I noticed today, the vacuum tripped the Y switch. This is new. Anyway, everything is grounded to everything else. From the spindle to the Z carrier to the rails to the aluminum bed to the control box to the MX4660, all grounded together. The reading is around 8-10 ohms or less allround. Shielded cables used throughout. I have some .01UF capacitors on-hand but not installed. The problem has to be electrical noise, but I am out of ideas where to look. Ant ideas? Thanks

[mactec54]

Everything pretty much works except for a weird limit switch issue. I use hall effect switches. On the Y axis, the sensor is mounted so it moves over the magnets. One magnet is used for Y Home and Y++, and another magnet for the Y--. For some reason, if the Y-- is set on, I get switch activation at random intervals. Usually it is so often I cannot do anything. Simply disabling Y-- makes the problem go away for the most part. Its a magnet about 48" from Home & Y++. The debounce is set to 5500. The Index Debouce is set to 10, but I don't know why.

And I noticed today, the vacuum tripped the Y switch. This is new. Anyway, everything is grounded to everything else. From the spindle to the Z carrier to the rails to the aluminum bed to the control box to the MX4660, all grounded together. The reading is around 8-10 ohms or less allround. Shielded cables used throughout. I have some .01UF capacitors on-hand but not installed. The problem has to be electrical noise, but I am out of ideas where to look. Ant ideas? Thanks

Sounds like you have some serious wiring problems to be have these problems

[A_Camera]

... everything is grounded to everything else...

This can cause a lot of problems. If you don't know what you are grounding you may introduce a lot of new issues instead of solving them. Basically, there is no point in optical isolation if you ground them and connect to your frame and everything else.

Of course, it can be your limit switches which are not meant to be used in machines, or just simply wiring issues. Don't add any capacitors on ANY limit switches. No, the problem is not necessarily electrical noise, can be bad wiring or even bad BoB or other components. Don't blame everything on electrical noise and don't assume you have done everything right just because "everything is grounded to everything else".