Homing not working but E Stop In is ?

Hi all,

I'm just building my control panel for my CNC project. I'm a complete newbie to all this and I've come across a small problem.

I'm using an Arduino Mega as the "brain" of the machine. I want to be able to manually set the machine to "home" via 3 buttons on the control panel (X home, Y home, Z home).

I've got a generic Chinese Breakout Board.

Within StepConf I configured pin 11 to be "Home X".

When the Arduino detects the "X home" button pressed I send an output of 5V to the breakout board. But it doesn't seem to do anything?

I tried clicking the "invert" box in StepConf but still nothing.

I tried changing pin 11 to be "E Stop In" in StepConf and I can then see the Estop coming in and out on the LinuxCNC software when I press the "X home" button on my Control Panel.

I have set a position for x home of 100.0 in StepConf (the motors aren't connected to the machine at the moment as I've not yet built the machine so they can just turn forever without a problem).

If I go into the software and click "Home X" via the software then the X motor just keeps turning forever (i.e. way past the 100.0 setting). But putting either 5V or Gnd on Pin 11 doesn't mimic this behaviour?

Anyone know where I'm going wrong with this?

Thanks for any help you can give as I'm tearing my hair out (what's left of it). I realise it's hard to visualise my set up so if yoU want me to post pictures or more info then please ask.

Thanks

The parallel port I played with has active low inputs so it probably does not see the +5v signal from the Arduino. I would take the Arduino out of the equation for now and get the BOB to recognise signals on its inputs and once you understand how it works, introduce the Arduino and any supporting circuitry.

Thanks Rod

I did try taking the Arduino out of the equation and just shorting the Breakout Boards own 'ground' on to the input and that didn't have any effect.

So, then I thought that maybe the input was goosed but it works if I set it to be the "E Stop In" signal?

Strange one eh?

andypugh wrote:

The home-X button won't do anything unless the machine is in homing mode.
You should see the machine turn off if you configure it for home + limit.

Or are you expecting that input to _cause_ the X-axis to home?

That's exactly what I was expecting? I expected the motor to do the same as if I'd chosen "Home" through the LinuxCNC software?

Is that not the case then?
How do I put the machine in "homing mode"?

Thanks for your help

andypugh wrote:

You would need to connect that input pin to the HAL pin "halui.joint.0.home" but I do not know if stepconf knows how to do that.

I've certainly not seen "halui.joint.0.home" in the text within StepConf anywhere.

What does the Home X option or the All Home option do then?

If it only 'homes' when that halui bit is on but there's no way to set that bit within StepConf it seems a bit redundant?

Thanks again for your continued help with this

Ahhh, that makes sense. I think I've proven that my buttons work. Now I've just got to understand how to get the machine to actually "Home" and what that entails.

Here's a bit more detail on what I'm trying to do...
CNC Pictures

I've posted a picture of my Control Panel. I want to have 3 physical limit switches on the machine that will represent the "Home" position (basically moving the machine up and across to a corner).

I also thought it would be good to be able to 'manually' tell the machine it was Home. Hence the homing buttons on the Control Panel in that picture.

If I set StepConf up so that the inputs are "Both Limit X + Home", "Both Limit Y + Home" etc then I get a "Joint on Limit Switch" error within LinuxCNC (see the photo via that link I posted).

Is this set up impossible to achieve just directly through StepConf?

If so, what file am I editing to try and get it to behave this way? Is it the .ini file in my CNC folder or the .hal file? (or both?!?!)

Sorry if these are really basic questions but I've never used Linux before and I've not had any CNC experience before either. So this is quite a steep learning curve. Thanks again