I’ve built the entire kit and I’m down to the final aspect of the build which is wiring. I have what I believe to be some basic questions.
My kit came with 3 Limit switches not 6. I’ve installed them so that there is one switch on the Z axis on the bottom. There is one on the X axis and one on the Y axis.
I don’t understand how this is going to work if there aren’t 2 limit switches per axis. How will the machine know the limit on the other ends where there are no switches?
Are the limit switches for determining where “home” is?
I have 4 stepper motors, one for Z-Up and down. One for X-Left & Right, and Two, for Y, Forward and Backwards. I am using a Tiny G board and there are 4 motor controls. Do I wire the two Y motors separately to Motor 1 control and Motor 2 control? So 2 individual wirings? Or do I tie the motors together and wire them to one of the drivers on the Tiny-G?
The limit switches r for homing and then u can set soft limits in grbl for the other end of each axis. Not sure on the steppers since I used a different board with my kit
I’m also in the process of installing limit switches, though I have had my Ox running for a month or so now.
Yes, the limits are used for homing. TBH homing is not super important until you want to change tool bits mid job. Though it can assist in resuming an aborted job i.e. I have aborted jobs that had the wrong feed rate and managed to resume, even without home switches.
It sounds like you have this correct, but just to check; the Z axis homing switch should be installed for Z-Max, that is the Z axis / tool in the highest possible position. X and Y should be installed at X min and Y min i.e. Left Front of the machine. (you can swap 2 wires on a stepper to reverse direction, or reverse the axis if you driver config allows if things move the wrong way)
The other thing that I am looking at is making a Z-Probe for Z-min. This can be as simple as a crocodile clip, a square of PCB (of a known thickness) and some wire. You connect the crocodile clip to the end mill and place the PCB on the top of you material and run the Z-probe command in your software and it will set Z 0 to the top of your material.
Have you downloaded Serial Port JSON yet? Your tinyg settings can be changed pretty easily from Chilipeppr. Go to http://chilipeppr.com and in the lower right corner, click download JSON server. After downloading and running the file “serial port JSON” I know your not quite that far along yet, but I remember that being kind of a hurdle when I first got my OX assembled. If you have any questions, feel free to ask, someone can help you out. It just tricky the first time.
For what its worth, I’m still running my OX with no limit switches, you don’t NEED them, but it can help out with not crashing when you are first starting out.
Good luck! It’s a lot of fun getting these machines up and running. http://chilipeppr.com
You guys are giving great advice! @Jeremy_Arnold I could have put my own words about homing switches in better terms. @AMBRO_Manufacturing do set all of them to NC (normally closed), type $$ in the serial port, read down.
My TinyG config can be found here: dhylands/TinyG-Utils/blob/master/Config/http://TinyG-20150423-135312.config.show note that motors 2&4 are both mapped to Y but with opposite polarity
I’ve been running my Ox without limit switches, too. However, I have not yet tried to do a job with a tool change (or multiple passes) which seems like re-homing with limit switches would help make sure you’re in the same position when starting the second step/pass. I have been sitting on some induction sensors that I intended to use for this, but haven’t gotten around to yet. I’m planning to rewire my Ox and I’m considering moving away from the TinyG board, if only because of Chilipeppr being the only g-code sending host option. I know it is theoretically a step backward, but I’m considering an Arduino Uno with a grbl shield if only because of the wider array of available hosts.