Thank you Sage for your time to prepare the schematic but you guys are working from the control box to the limits which is easy if I was starting my wiring from scratch. But this is not the case.....

It took me some time but had to figure out a way to do minimum wiring changes because all wiring is permanent attached to the machine. Finally I did it as per attached schematic and I’m happy now.

All limits are working fine and the touch plate also works fine. I test it and she went down and soon she touched the plate she went up 1”, wonderful

The only thing I don’t understand is that on the inputs screen, all limit switches are active high (I mean the box is NOT ticked and remains red) but the Probe and the ESTOP are active low (the box is ticked and is green). Don’t know the meaning of that but I assume it is ok because everything is working.

Also on the diagnostic screen there are no LED’s on and when I touch the alligator clip to the touch plate the Digitize LED comes on. The same for all limits when I manually close the switch the LED comes on and the reset button bibs on.

Thank you all for your help. if I knew that I would have gone thru all this trouble perhaps I wouldn’t have bother with the touch plate LOL, but in the end I’m very happy thanks to all of you.

Well I thought I was all done but I was wrong

In order to have the gantry squared with the home switches, I need to have the Y and A switches on separate terminals in the BOB.

Based on the schematic I provided just before this post, is there any way I can do that within the control box or by switching the wires on each limit switch?

Very sorry, forget about my last post.

I think I got it and I will do the change tomorrow

Good. I hope it all works out.
I'm curious what VB script (program) you finally used. The one in your instructions, the One Tweakie posted or the one I linked to.??

If you haven't already, you might want to use the one I linked to (it's halfway down the page). A lot of issues were found and corrected with some of the simpler programs. I found a bug the hard way in that if you happened to be in G91 mode  (incremental mode) when you run one of the early tool zero programs the tool would jam itself into the table. That problem was corrected and so were quite a few others. Just remember the one I linked to has it's plate thickness and return measurement in millimeters. Tha't easily changed. All of the development on the auto zero system was done by the gentleman on CNC zone. He frequents that forum and answers questions for people regularly.

Sage

Also. If it's working that's good. TO explaing whay the settings need to be apparently reversed - It may be that your BOB has some logic in the line which reverses the level of the signals. Perhaps an optical isolator or a transistor switch or something. That's not very nice of the manufacturer to throw that curve at you but I guess it's something you'll just have to remember. Keep good notes and diagrams. Trust me, in a couple of months when you forget everything and you have problems, a good record of how it's all supposed to be is priceless.

Sage

Glad to hear that you got it sorted Nicolas.

What are you going to make with this machine ?    Don't forget to post some pictures of your work.

Tweakie.

Today I will put back the wiring for the Y & A as it was and install them on separate terminals so I can have my gantry squared when I want and then I will revise the wiring on X & Z the same way I did for the Y & A. Hopefully no more wiring changes are needed.

Sage I used the original script I posted here at the beginning of this thread. Sorry I’m an old timer and millimetres are like Chinese to me LOL. However I kept the one Tweakie posted here and one day I may try that one. I try to keep good records of all the work I’m doing.

I’m only doing hobby work Tweakie and I plant to make the bearings housing for this machine out of a 3ft long aluminum bar I got 1" thick by 2" wide (now they are plywood) and then make the NEMA 23 motor supports out of a 4ft long aluminum bar I got 1/2" thick by 3" wide. After that some engraving or mechanical parts for my next machine. This is my 2nd CNC I built in the last two years and my next one I would like to do it with 8020 aluminum members.

I have posted a video for my present CNC http://www.youtube.com/watch?v=xJvCtoMv814
On the video she runs the “break in code” I got from this forum and she runs at about 100 IPM. This is the first run of the machine and you will notice a clicking sound in the background which now is fixed (misaligned anti backlash nut on the X axis)

Thanks again

Very nice video Nicolas - I like to tool store on the rear of the X Axis 

The Probing script I posted was only for trial use as it operates in a different way to the one you were already using and was intended just to try and identify the problem.

As Sage mentioned, the auto tool probing scripts have advanced as Mach revisions have occurred so the one you currently have may not be the most reliable - you may want to update this at a later stage.

Good fortune with machining aluminium - a router is not really a suitable tool compared with a mill when it comes to metals (it's a rigidity issue as well as coolant and chip clearance) but nonetheless it still has to be tried.

Tweakie.

If the code you have works for you that's good. I'm not familiar with the VB code programming too much.
Just be aware that if it's like some of the earlier codes, If you should ever use G91 mode somewhere in your milling operation and leave it there,  when you do a tool zero setting it might try to put the tool through the table. Can't say for sure.
 The newer programs save current settings, do the tool setting with the correct parameters and then put the old ones back.

Sage

If you use more than one tool a lot, then you might want to consider using the two plate zeroing system, where one plate is fixed, to give you a reference position. This allows zeroing after a tool change to be fully automatic. I've incorporated it into my 2010 Screen. It works in both inches and mm's, and has a ton of safety checks built in to try to prevent the user from doing any damage.

http://www.youtube.com/watch?v=7np99wSr9c8