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Offline kolias

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Probe Wiring
« on: June 29, 2022, 02:50:35 PM »
Not sure how to wire my home made probe and I came up with the attached wiring.

Do you see anything wrong?

Thanks

Nicolas
Re: Probe Wiring
« Reply #1 on: June 30, 2022, 08:41:03 AM »
Which wire is the probe?

Offline kolias

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Re: Probe Wiring
« Reply #2 on: June 30, 2022, 09:55:37 AM »
I don’t understand the question John, it’s a simple homemade gadget which sets the tip of the cutter 1” above the piece to be cut and then it zeros all DRO’s.

The touch plate is 1/4" thick aluminum plate and the alligator clip is attached to the spindle. So I would say the alligator clip is the probe.
Nicolas
Re: Probe Wiring
« Reply #3 on: June 30, 2022, 10:27:35 AM »
OK.  So the plate is presumably isolated and grounded via the tool or whatever in the spindle, right?  That's normal practice.

But your diagram shows the clip on the touch plate so it is permanently grounded!  The touch plate should be connected via the pullup to +5V.  If you need an alligator clip to do that then fine.  Normally you could rely on the spindle being grounded anyway but you might need another clip and ground wire to make sure.  I've not found it necessary but it depends on the machine.  Commonly the "probe" is a precisely dimensioned thing that's held in the spindle when the machine is being referenced.

Given some reinterpretation your wiring is OK, though I think 120R pullup is a bit low, you will be sinking 40mA odd.  1K would probably do the job.

Offline kolias

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Re: Probe Wiring
« Reply #4 on: June 30, 2022, 08:34:48 PM »
Thank you John, yes the plate is isolated and grounded via the alligator clip on the tool. Sorry about my diagram which is wrong but it only shows the principal. I will change the resistor to 1K.

My “probe” is far way from a proper tool but it does the job nicely and have been very happy with it.
Nicolas

Offline kolias

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Re: Probe Wiring
« Reply #5 on: July 07, 2022, 02:24:18 AM »
Sorry John but I’m always confused with the pull up/dn and active low/high.

To be on the safe side on the Mach3 input signals screen and Active Low Column, the probe should be set to what? Green mark or Red?

Thank you
Nicolas
Re: Probe Wiring
« Reply #6 on: July 07, 2022, 03:15:32 AM »
Green tick selects active low.

Offline kolias

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Re: Probe Wiring
« Reply #7 on: July 07, 2022, 01:42:35 PM »
Thanks John

Finally the probe wiring is done and the active low is selected. My script is:

Message( "Auto Zeroing..." )
If IsSuchSignal (22) Then
code "G31 Z-3 F20"
While IsMoving()
Wend
Call SetDRO( 2, .367 )
code "G1 Z1"
End If

I still left the “G1 Z1” for now but I will change it the G0 as you suggested. I also installed the 1K resistor.

However on testing the probe, when the Z started to go down I manually lift the touch plate to touch the tool and the Z axis still kept going down (it should have start the retract) and so I hit the E-Stop.

Perhaps the code line "G31 Z-3 F20" may create this? I interpret the Z-3 as it must go down 3”

Any ideas ?

Thanks
Nicolas

Offline kolias

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Re: Probe Wiring
« Reply #8 on: July 07, 2022, 01:45:10 PM »
Forgot to mention that on the diagnostic screen there are no lights lit but when I touch the alligator clip to the touch plate the digitize green light comes ON
Nicolas
Re: Probe Wiring
« Reply #9 on: July 07, 2022, 03:36:47 PM »
The G31 Z-3 F20 is a probing move, causing the tool to go down a MAXIMUM of 3", but it should stop when the probe is triggered.  Only if the probe input is not triggered will it move the full 3".  It sounds like your probe (digitize) input isn't being registered.  You can make a probing move from the MDI without writing a macro, just type in
G31 Z-3 F20 and check that grounding the touch plate stops it.