[edsutterjr]

I have an X-Carve, with some software that I wrote to drive it with a Raspberry Pi.
My machine (and the Pi) are in my garage, and I connect to it over WiFi from a
different room in the house. It is running Grbl 1.1g. Love it, works fine. Except for...
A few times now I've turned on the Pi and the router and I walk back to my office
and connect to the Pi over WiFi and start the GCode feed.
Since the Pi is plugged into the controller, it apparently powers the CPU and GRBL
responds; however, the stepper motors are not powered. As a result I start up a
cut, then come back only to find that the router hasn't moved because I forgot to
turn on the power to the X-Carve controller.
Is there a way to query the system to determine if the motors have power?
Thanks,

 

[MikeMa]

Unfortunately the communication to the drivers and steppers is a one way communication, so there is no way to determine if they are powered up.

If I am reading this right, you are running the machine remote from somewhere other than the garage? If this is correct, this is a very unsafe setup. Just as you wouldn't remotely turn on a table saw or other cutting tool, you wouldn't want to do this with a CNC. You should never leave your CNC running unattended. That bit creates a lot of heat while cutting, and it would not take much for something to go wrong to start a fire.

My CNC runs on LinuxCNC and as a result runs on a PC running Linux as its OS. I do remote into that PC frequently, usually from my desk which has dual monitors which comes in great when researching configurations. I will NEVER make my machine move from a remote connection. NEVER. After making my changes, I will walk out to the garage to test them, where I would need to power up the machine and release the e-stop.

 

[edsutterjr]

Yea, I agree with your caution. I don't want to remotely start anything other than the Gcode stream. I need to be next to my machine to turn things (Pi, XYZ controller, Router) on, but sometimes I turn on the Pi and the router but forget to turn on the motor controller. My "remote" location is about 10 steps from the garage. Several times I've walked to my console (forgetting to turn on the motor controller), started up the gcode stream, then walked in to check on things only to find the router just sitting there. If, when I started the gcode stream it could tell me the controller was off, I wouldn't have to restart things.

My setup is small and covered (see picture), not in harms way (no kids, and my wife doesn't go near the garage). I'm one room over, and want to avoid the extra steps to restart the stream because the controller was off.
Thanks,

 

[MikeMa]

Again, this is a very dangerous, and at the very least you will get ruined work pieces and broken bits. Starting the gcode stream is the same as turning on a table saw and pushing the work piece through. You would not do that remotely. I know from experience that the time I press the e-stop the most is within a few seconds of starting it, typically because something wasn't setup quite right. Those 10 steps from another room can mean the difference of stopping a cut in time, or at best a ruined work piece or a broken router bit, or at worst starting a fire. The correct steps for you to take is put a monitor, keyboard, and mouse on your RPI and control your CNC when your standing next to it. Not so long term, this will be the cheaper option. Or if you really want to get spiffy, put a touch screen on it, and that would still be a not so long term cheaper option. This will also solve the issue you posted about initially. Another advantage of this is when you remote in, you are putting more burden on the CPU, which can and will lead to lost steps.

Another example, I work from home most days. I have CNC job waiting that will take about 2 hours to run. My desk is within ear-shot and I have cameras in my shop. My CNC is sitting idle right now, and I won't start the job until I am off work and can give it the full attention it needs. These are wonderful machines that can do some amazing work. They can save you some time by allowing you to work on other things while it is running, but those other things need to be in the same room of the CNC. When my CNC is running, I am typically in the shop sanding something, tidying the shop up, or something that is in the shop.

 

[edsutterjr]

Hmmm... good idea to just mount a small display/buttons to the pi, then I can just download the gcode file over wifi and do everything else locally. Amazing how cheap this stuff is.
Thanks,

 

[MikeMa]

Yep, just looked on amazon, no reason you couldn't get a monitor, keyboard, and mouse for around $100 with a few minutes of looking. That is more or less the setup I have. I setup samba on my Linux controller (samba is available for PI OS too) and I just copy my gcode files straight to the computer from my Windows laptop.

 

[edsutterjr]

I do all the work on my "in house" PC (mostly Easel), then just ship the gcode file over to the Pi to feed to the machine. For that reason, plus the sad fact that I have very limited garage space, I'll probably stick with the smaller LCD/Button setup. All the Pi will do is kick off the gcode feeder. I could just mount that to the PVC frame in the front and be done...
Thanks again for the feedback...

 

[old55]

Welcome to the forum @edsutterjr

 

[edsutterjr]

@MikeMa I just had another thought (even cheaper)...
I'll add a web-server to the backend of my gcode feeder, then all I need is my phone to control it...

 

[jw2170]

Welcome to the forum, Ed,

 

[keithmart]

Why not transfer your files from the house via a USB memory chip? that way you would have more control.

 

[edsutterjr]

Why not transfer your files from the house via a USB memory chip? that way you would have more control.

@keithmart, yea I could do that, but the Pi has WiFi built in already, so a wireless transfer is just easier.
I've been thinking about this a bit now, and I'm still headed down the web-server path using my phone as the control panel. From the "safety" point of view (as @MikeMa has been rightly emphasizing), this doesn't force me to be local to the machine, but unlike my current solution, it does "allow" me to be close to the machine, and I agree with all his points of caution. So now its up to me to just do the right thing and stay close by while the tool is running.
Thanks!

 

[TimPa]

Is there a way to query the system to determine if the motors have power?
Thanks,

first thing that came to mind is to connect a wire from the power supply you wish to monitor, to one of the Pi inputs, either directly if it falls in the input voltage range, or if not through an intermediate relay...

then query that input.

 

[edsutterjr]

first thing that came to mind is to connect a wire from the power supply you wish to monitor, to one of the Pi inputs, either directly if it falls in the input voltage range, or if not through an intermediate relay...

then query that input.

Yep, that would do it. I was trying to avoid any additional wiring; plus, based on earlier discussion in this thread, I realize it's better to just "be there" (next to the machine) when starting up a build. Thanks!

 

[TimPa]

Yes, Mike is spot on as usual. i was just responding to your post...

 

[keithmart]

Yes, Mike is spot on as usual. i was just responding to your post...

ooops!!!

 

[edsutterjr]

Yikes!
Understood, thanks!

 

[MikeMa]

Thank you for posting that video @TimPa! In my machine tool box, I have a 3D printer, a 40W CO2 Laser, and my CNC Router. Two of those use heat to work. One has heat as a byproduct. All three have a fire risk and should be monitored while running. However, of the three, in my opinion the one that creates heat as a byproduct, has the highest risk of starting a fire, and that is the CNC Router.

I just configured a game pad to work as a pendant for my CNC, and able to assign functions to various buttons on the gamepad. The gamepad is wireless, and is great for work piece setup and have buttons on that trigger the touch plate scripts. One function that I assigned to a button is an "Abort" function which works similar to the e-stop. This allows me to focus on getting the work piece setup and stop the machine if something goes awry when running the touch plate scripts. Yes, even when the router is not running, the machine is capable of causing injury and damage, so I have that button, and the e-stop within arms length. The one function that I have not, and will not, assign to a button on the game pad is the start button. The reason being, is EACH and EVERY time I go to start the machine, I go through a mental checklist before I start the machine. The movement, which is one step, from the machine to the computer controlling the machine is part of that checklist, and ensures that I go through the rest of it. This checklist includes things like making sure the bed is clear of anything but the work piece, the work piece is secure, the router switch is in the on position (always switch it off between operations, even though the CNC controller will power it on and off), the correct file has been loaded, and several other items. ONLY then do I hit the start button. Then I watch the machine like a hawk to make sure it moves as expected, and make sure the first few passes go as intended. For this entire process the E-Stop button is always within easy reach. Only then do I free myself to work on other things while staying in the shop.

These are great machines and can do amazing things, while increasing your productivity. Please use them with safety in mind. And for what it is worth, I do not think a CNC is any more or less dangerous than any other tool in our shops. Any power tool is very capable of starting a fire, causing damage, or even injury. All deserve and demand a high-level of respect when being used. Be safe my friends!

 

[maddog]

Watching that video clearly showed the piece was not mounted correctly. You never use one of two small clamps to hold a piece of that size. It pays to properly clamp or screw your pieces down. It's bad habit or laziness that cause events like this to happen. Thanks for the video.

 

[CharleyL]

Stepper motors always get hot when powered. After running for a while, are they? If cold there is no power going to them. (don't burn yourself)

Charley