Conductive Touch Probe - Input 7 and Input 6?

[Ziggy]

Hello

I am still building my system based off of a Onefinity machine.

I have a simple conductive probe that uses a magnet to touch to the tool and a aluminum plate that sits on the surface. This is a two wire setup. I followed the schematic I found in the library here. <See attached Touch Probe.pdf> I can confirm by looking at the input indicators (Alt-I) that it is triggering input 7.

Yesterday I was doing a little reading during lunch about how to set this up in the software. So I found the Acorn Probe Setup document online. <also attached> and noticed that the schematic for the normally open conductive test probe also shows another input going to In 6. (Pages 11 and 12)

Input 6 is labeled as a detection circuit.

Is this detection circuit used so that if you forget to remove the probe you can't start a job? I know that sounds silly but I have read where people have started their router/spindles with the probe still attached.

I am using a 3.5mm audio jack to connect my probe. This jack has the capability of opening and closing a contact when the plug is inserted. I could use this to connect to Input 6. This would be a nice safety feature if my above speculation is right.

The only issue is that I have already built this thing with a two wire circuit and it would be a decent hassle to pull all that wiring. However, I am willing to to that if I haven't incorrectly speculated about the detection circuit.

Am I correct in my assumption about Input 6? The reason that I ask is that the first schematic doesn't show anything attached to In 6.

Thanks as always!

[cncsnw]

Yes, the detect signal is used to prevent you from starting the spindle with the probe in place.

It is also there to prevent you starting a probing cycle with the probe not in place.

[Ziggy]

Thanks! I will just use the old cable to pull the new cable in. Better done right... plus I could see myself leaving the silly probe attached.

[ShawnM]

I think you are confusing a tool touch off with a 3D probe, they are not the same. The probe detect input is to tell Acorn you have a 3D probe actually chucked up in the spindle.This input activates a few safety features to protect the expensive probe as Marc pointed out. You don’t need this input for a conductive tool touch off because the tool is actually in the spindle. Your tool touch only needs one input, probe tripped.

You could simply add a warning message to your tool touch off macro to remind you to remove the magnet from the spindle.

If you have steel bearings in your spindle you don’t need the magnet on a wire as the tool would be grounded through the spindle. Does this mean you have ceramic bearings in your spindle?

[Ziggy]

This is just a cheap HY spindle so I seriously doubt it has ceramic bearings.

So if I understand correctly I could simply have the one conductor going from the touch plate to IN7? Since the spindle is grounded this will close the circuit?

The reason I have it the way I do now is because this is the setup that came with my original controller. The machine was originally designed to be used with a Makita palm router. I have upgraded to a spindle and Acorn board on my own.

If I could get away without having to use the second wire it would be fantastic!

[ShawnM]

If the machine and spindle is grounded properly, yes, you can use a single wire into any input and set to "probe tripped" with spindles that have steel bearings. I've done this a few times on some of my early retrofits where I used a conductive plate for tool setting. To verify, simply check continuity between the tool in the collet and your common ground bus bar.

That said, I highly recommend down the road you look into getting a tool setter that is spring loaded with either an optical switch or proximity switch. These will save your bits. I no longer use conductive plates for touching off the work surface. Just my 2¢.