How to set up Eleks machine limit switch in T2 Laser

  • Hi guys. I installed my limit switches and even soldered them very well. But, once I tried my laser it was cutting mirrored images. I resolved this by inverting the axis. Great now it cuts well but after installing limit switches, then home them to 0.0 then move the laser into position for cutting. It shows my coordinates in negative. I was looking into the settings of grbl but don't know which $$ to change.. could you help me ? 0_1511358335244_IMG_20171122_001031.jpg 0_1511358440084_IMG_20171122_001024.jpg
    Will it be better to just move the whole board and limit switches to the opposite corner ? (I don't want to do that kind of :/ )

  • Developer of T2Laser Software

    @rolx Usually the control board is at the back but it doesn't matter as long as your home switches are at located at what you consider front left.

    Once it locates the home switches the machine coordinates should be set to 0,0. If there's an offset I would clear them using Clear Grbl Positions in the Machine menu.

    If the switches are positioned as limits rather than home switches you can still use them, but would need to change some parameters and then setup one of the custom buttons to go to your home position and reset the workpiece 0,0. Yes the machine coordinates would be negative but this is no problem and actually fairly normal in the CNC world.

  • @Zax so there isn't any way to make them positive. That means I should just be careful to insert the coordinates every time negative.
    I have them just for homing. I still haven't tried cutting with it after installing the homing. Will do today or tomorrow. But won't the image be upside down again ?
    If you look at the photo front left are the switches. And after i put it into the position shown on the other photo it is negative. Now if I want to cut the paper, won't the picture be on lower left instead of upper right ?
    EDIT: Ok my problem was that I had changed the Y cables in my stepper motors. That way it was going the opposite way. Now in the software my arrow up means go up, right arrow the machine goes right. Perfect.
    But the problem with homing still persists. The homing goes the other way. Not left bottom but to right top.
    EDIT 2: I changed the $ homing invert to 3 and now it goes hoe it should.
    The problem with negative coordinates was that the LaserGRBL software wasnt supporting negative ones.
    Thank you for your support, I can now start making what I want :D

  • Developer of T2Laser Software

    Negative machine coordinates don't matter, change the display to show workpiece coordinates and use the custom button like I suggest. It will home to your limit switches, then you press the button and it will move to the lower left or center if you prefer and then set 0,0.

    Let me know if you need help setting up the custom button.

    The alternatives are to recompile Grbl with what you need or put in an automated move after homing but that's not recommended for safety.

  • @Zax
    I am awaiting delivery of my engraver and would like to add switches as described to automaticaly set the home position. I understand how they should work and will have no problem soldering to pin 9 on the arduino, but how do I get the machine to auto home on switch on? (how does it know the NO switches are connected) Is it a link on the board, a setting in T2 Laser or modified firmware (if so where can I download it?)

  • Developer of T2Laser Software

    @ztf Home switches are the best upgrade you can make. If you are using my default Grbl 1.1e firmware, just enable them from the settings menu and that's it.

    You connect 2 normally open switches in parallel from D9 to Gnd, one for the left and one at the front. Once enabled in the menu the house icon will change to red indicating it is going to auto-home, when you click it the head will move left to the switch and then back off, then forwards to the switch and back off. Then it sets that as machine 0,0. You can use the preset positions to move to any location accurately.

  • @Zax
    thanks for the quick reply, I have found the setting in the menu (I was looking in the wrong place) Where can I download your firmware (and is it different to any other Grbl 1.1e?)
    Sorry if the answer is obvious, but I'm new to the laser scene!

  • Developer of T2Laser Software

    @ztf The T2Laser default firmware is Grbl 1.1e (I compiled it, many others use it), it's in the Machine menu. I also include various custom firmware options including one for 3-axis homing and other purposes.

  • @Zax
    Ok, thanks for that, I did see it in the menu but wanted to make sure that it was the correct one for using the switches.
    (just waiting for delivery so I can make some smoke!!)

  • Where can I find a tutorial about how to add the home switches? What kind? How and where they are mounted, wiring, etc. Thanx!

  • Active Member

    here are several different methods including mine with pictures and explanations

  • Hi,
    I mounted two microswitches, one on the end of the X axis rail, set so that when the laser mount moves fully to the left it closes the switch, the other on the left front (nearest to the side with the control circuit) set so that when the X axis rail moves to the front it closes that switch.
    Both switches are connected in parallel, (common pins together and normally open pins together) then one set of contacts is soldered to pin D9 on the arduino the other to the ground connection. Set T2 Laser, control laser, settings, select "Home Switches" and that's it. (I fixed the switches in place with very strong double sided tape, works well but would probably be better to use nuts and bolts!)1_1519682714817_WP_20180226_21_45_35_Rich.jpg 0_1519682714816_WP_20180226_21_44_56_Rich.jpg

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