the ESS should be on it's own 5vdc line with a common (earth) it the best way to do it, a lot of noise problems I was having went away after I rewired the whole machine to a common and it`s own 5vdc line for the ESS.

and moved the high and low common and power wires so there was no side by side wires, a cross over at one spot what is fine and the high and low common have there own star point side by side what is also fine.

so you have a clip that goes to the tool what is earth (common) and the signal wire going to the touch plate.

ground is the ground pin on port1 between pin 15-16 and signal wire is pin 15 on the C25 board

also what is the voltage between the clip and the plate if it is below 2.8vdc that might be the problem.

4v

Have you got a separate 5v power supply you could try

I do have a separate 5v power supply, you can see it in the attachment

the ESS should be on it's own 5vdc line with a common (earth) it the best way to do it, a lot of noise problems I was having went away after I rewired the whole machine to a common and it`s own 5vdc line for the ESS.

and moved the high and low common and power wires so there was no side by side wires, a cross over at one spot what is fine and the high and low common have there own star point side by side what is also fine.

The power supply I installed for the ESS is grounded to the chassis, common to the earth ground of the 220v from the house. What I'm unclear about is there are now 2 grounds, one from the C25 board and one to the chassis/earth from power in from the house. The power supply I installed  has line, neutral, and ground, the ground on the ESS is derived from 5vdc- from the 5v power supply I installed, where s the common ground for the vdc? The chassis is grounded VAC, the ESS/C25 is VDC. I'm probably not understanding how the grounding works but hopefully some one can straighten me out.

you have not got your commons connected quite right -common is earth, ground you can have a +common (what is Power) and a -common look it up use google you need to learn this it is important that you learn how to do it.

You have a major ground loop problem....

Remove your power supplies 0v outputs from the chassis earth for the control box

So just feed the ESS and bob with +5v and 0v

And just feed your stepper drives with +v and 0v

Then try your probe routine.

Rob

If your machine is earthed .... By clamping pin 13 or 15 of your bob to your spindle you are essentially making the bob power supply +5v = +1v (same potential as the control box chassis) and the 0v is -4v ( below earth voltage)...

You have two isolation transformers there and you do not need to connect the secondary side 0v lines to earth, control box chassis earth or the machine earth (all earth's should be the same voltage)

It sounds like if you machine was earthed... When you claimed the pin 13/15 from the crocodile clip onto your spindle... You were also trying to apply +4v (because of the voltage divider I noted above) onto the same 0v line.

Rob

Rob

bang on Rob, (the common to the earth ground of the 220v) this ground should be sunk to earth as not connected to the machine but being connected to the earth stack as it will be, you only earth the main power supply wire if you are told to by a electrician you can wrap a shield wire around it what would go to the high voltage common.

also what I said above was checked by an electrician

Earthing is very controversial (and emotive) .... Many countries have different ways of doing it and providing an earth (each think they are right)

... Long and the short ...

If you have an ac supply from the street (electric supply company transformer) ... It needs an earth ... As the transformer in the street will be earthed ... So that if you measure between any of the incoming wires none of them will exceed the supply voltage relative to earth...

Does everything need to be earthed... That depends on that voltage is going into the object relative to earth, and also how the supply is wired to detect current flow to earth (should a problem occur and something becomes a higher voltage relative to earth) .... In the UK the use of residual current disconnection devices has become very common in some scenarios so that current flow between the two current carrying wires is monitored and should a difference occur above a prescribed amount for a prescribed time the supply is disconnected.

It is one reason why I choose not to earth my machine but my control box is earthed.  (Another is I've had more 230v shocks in my life than I care to admit...and I'm still here... (Some were not my error I must point out the most interesting of which was when I was on a ladder and touched the top of a metal stud wall to steady myself with one hand and used the other to try to lift a metal ceiling tile... The funny thing was my brain had to figure out what the sensation was ... Only for me to confirm it by checking it for a second time ...

"Electrician never had an electric shock has never done any work"... It gives you a healthy respect for moving slower and thinking more when you are working on 415v or above when your room for error diminishes...)

If you are vetting an electrician ask to have a look in his toolbox ... If the tools are old but show little or occasional old flash marks ... He's relatively safe and experianced... If the tools are new ... He's inexperienced or covering something up ... And if they show recent flash / burn marks ... He's still learning...

Rob

sounds about right

So this is a lot to understand but what I'm getting as the take away is that I need to eliminate the 220v earth/ground. The 5v power supply I installed does not want to share it's ground with 220v earth. I've attached a schematic of how the machine is wired at the moment. I added, I guess foolishly, the 220v earth, that was not originally installed when I got the machine. Any how Could you please look at the schematic and point out the flaws in grounding.  You talk about 0v I'm unclear as to what is 0v in the schematic the 5v power supply has a line, neutral and ground input and a v+ and v- out where is the 0v in the schematic?
Thanks again for helping me out!!

What you have drawn is correct... Except don't remove that earth...

What I was talking about (the 0v) is what you have drawn as v--... Alot of people connect them together and then connect them to the chassis casing via the earth lug

I would suggest you go through your wiring and double check you have wired it as you have drawn it

Sorry need to go to day job to pay the bills

Rob