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Author Topic: Setting up a touch plate in mach  (Read 4025 times)

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Setting up a touch plate in mach
« on: September 29, 2013, 11:00:54 AM »
I have a 4848 zenbot that using 4 stepper motors (2 motors on the x axis)  The motor controller  a gecko 54 is using a db9 cable wired to 3 limit switches for homing.  Shaun over at zenbot set it up for me I would like to setup a touchplate but Im unsure how to proceed.  Im assuming the 3 limit switches are using 6 of the 9 wires.  With a continunity tester I can find the 3 unused wires
How do I proceed from this point in the mach 3 config screens Thanks Robert

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Re: Setting up a touch plate in mach
« Reply #1 on: September 29, 2013, 12:54:44 PM »
   Are you familiar with Mach and its settings?

   Mach wil allow you to assign the pins for inputs and outputs etc. Many machines are set up to only use 1 pin for all of the limit switches. Since Mach knows which axis is moving and in which direction it thinks the next trigger will be the axis in movement. It will zero that DRO and move to the next axis to be referenced.

   Now the reason I asked and stated the above was to have you verify which pins are being used in the "inputs" section of Mach. You need to find which input pins are available. You will need 1.

   To make and or use a touch plate, the easiest thing is to buy a piece of PC (printed circuit) board. This is available at RS in small pieces which is all you need. Solder a long wire to it. Lay this on your tables surface, conductor side up. Attach wire to input, enable the input. test connection on diagnostics page by manually touching the plate to your tool tip. Does the light on the diagnostics page indicate the circuits status has changed (does the light for that input light up upon touching the board to the tool?). Btw doing the manual test prior to use allows you to confirm you and your machines safety. Still guard the E Stop ;-)

   You will have to go in and set the thickness of the touch plate in the "offsets" page. This will 0 the axis upon touching accommodating for the PC boards thickness (if you entered the correct thickness).

   I hope that helps. If not ask more.
« Last Edit: September 29, 2013, 12:58:09 PM by Fastest1 »
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: Setting up a touch plate in mach
« Reply #2 on: September 29, 2013, 06:41:55 PM »
My plan is to solder a wire to a pce of metal I have thats about 1/32 thick.   I realize I may have to use the active low switch to start the z axis down to the work surface.  If my router is grounded correctly by the outlet the 1 probe wire should close the circuit and activate the touchplate.  To sum up I just assign any open pin to the probe signal (port 1? )pin whatever is open in the cable attached to my touch plate.
To use press AUTO TOOL ZERO?
« Last Edit: September 29, 2013, 06:51:24 PM by robjeffking »
Re: Setting up a touch plate in mach
« Reply #3 on: September 29, 2013, 08:37:50 PM »
So i found this script (PlateThickness = GetUserDRO(1151) 'Z-plate thickness DRO

If GetOemLed (825)=0 Then 'Check to see if the probe is already grounded or faulty
DoOEMButton (1010) 'zero the Z axis
Code "G4 P2" ' this delay gives me time to get from computer to hold probe in place, 2 seconds
Code "G90 G31 Z-1 F5" 'probing move, can set the feed rate here as well as how far to move
While IsMoving() 'wait while it happens
ZProbePos = GetVar(2002) 'get the axact point the probe was hit
Code "G0 Z" &ZProbePos 'go back to that point, always a very small amount of overrun
While IsMoving ()
Call SetDro (2, PlateThickness) 'set the Z axis DRO to whatever is set as plate thickness
Sleep 150 'Pause for Dro to update.
Code "G1 Z2 F50" 'put the Z height to retract to here
Code "(Z axis is now zeroed)" 'puts this message in the status bar
Code "(Z-Plate is grounded, check connection and try again)" 'this goes in the status bar if aplicable
End If
Exit Sub )
I paste this into the Edit script tab
ill use port 1 pin 15 in the probe tab
Bring the touch plate to the bit to test led is working
The settings in the script need to be changed/tweaked to needs but I think is most of the setup process correct me if I missed anything.