# Using two touch plates and the Mach Blue Big Tex screen with Mach



## bloomingtonmike (Dec 13, 2011)

I wrote this up for a friend. Thought I would post it here too. Two touch plates are used to make zeroing your Z/bit to the top of the work after a toolchange very easy.

On the Mach Blue Big Tex - look at the bottom and you will see two buttons - Initial Zero Setup and Tool Change Zero Setup. We will use this screen and those buttons.

You first install Mach Blue - http://www.machsupport.com/screens/MachBlue_setup.zip

Then you place the Mach Blue Big Tex in the mach3 directory - http://www.machsupport.com/screens/Mach_Blue_Probing_by_Big-Tex.zip

Then you load the screen - View, Load Screens, Mach Blue Probing by Big-Tex

An assumption here is your spindle or router is common grounded with your controller - You know it is with this screen if you can touch your spindle to an input pint and the green indicator lights up on this screen. If it does not work you need to connect your spindles ground and the controllers (DC) ground.

Shut down your controller. Disconnect power if your input terminals are by electro-sensitive components (raw wires or boards etc.)

Get two copper clad plastic boards - 2"X3"ea is fine. One will be used at your spindle. The second will be used at a spot on your bed.

I ran a wire from my control box (at the controller inputs location) through my entire Echain to the spindle and connected a port so the touch probe can easily disconnected. Using Male RCA connector cable and a female to female RCA connector is a cheap way to do this. Cut the cable in half. Solder both the RCA's conductors of one of the RCA pieces to in the wire you ran through the echain to the spindle. Mount it so the end does not ground anywhere. Solder the other piece of the RCA cable (both conductors) to one of the copper clad plates. Using the female to female coupler you can now attach that plate to the wire you ran.

Next pick a spot on your bed where your router does not typically cut but is still accessible by the spindle/bit. Keep this as close to where you normally mount your work so the tool change touch off is fast. You want this plate mounted flush with the bed of your machine. Run a wire from your control box to this spot. Solder the wire to the second copper clad plate and mount to your bed. Make sure that plate is not being grounded at all.

At the controller attach the two plate wires together and connect to an input on your controller.

Connect the Spindle plate to the RCA connector. Config, inputs, ports and pins, probe - make sure that is enabled. Also run the setup wizard for the probe and touch the Z plate to the spindle or a bit in the spindle (make sure the spindle is NOT running LOL). It should setup the port number automatically. Save your settings and exit config.

Now touch the plate again to the spindle - you should see a green light on the Big Tex Mach screen on the right light up showing the input is grounded for the probe.

Reference all home - go to machine 0x 0y.

Jog your machine to the center of the 2nd plate. Input that location on the Mach blue big text screen at the bottom where it asks for the X and Y of the fixed touch plate.

Also enter the thickness of your portable plate on the lower right under plate thickness.

Mount some work to your table and mount your first bit.

Jog to your work starting point and zero out your X and Y. You can lower z down to about 1" if you want from the work.

Connect the Z touch plate to the RCA connector.

Hold it below the spindle on top of your work.

When you press Initial Zero setup the Z will drive down and touch that plate. It will raise slightly and do it again. 

After that it will raise up and go over to the second plate (the coordinate you inputted) and drive down and touch that plate and again it will raise slightly and drive down again. It then raises to a safe Z height above the work and returns to work 0x 0y.

It has now stored the thickness of the work and zero’ d out Z and is sitting at safe Z.

Cut your first tool's tool paths. When that is done change the bit to the second tool.

Press Tool Change Zero Setup

Now the spindle will move the new bit over to the bed plate and just touch off there. It raises to the new tools safe Z height and has zeroed that new tools Z to the initial top surface of your work.

Use the Tool Change Zero Setup for the remainder of your tool changes for this job. 

Enjoy.


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