Limit Switches Issue on LowRider V4 CNC

LowRider CNC Troubleshooting
1

We just built a LowRider V4 CNC machine, Everything moves in the correct directions when instructed, both the Z motors move up and down in sync when we move Z up/down.

None of the homing limit switches on the the X, Y, Z Axis are working.

X, Y hits the limit switches and keeps going. No Effect.

Z Axis, Only the one motor moves. Z0 does not move, But when we use the move tool, both Z0 and Z1 motors move in sync, in the correct direction both ways. When Homing Z Axis, The Z0 motor does not move.

Things are working, Except when running the HOME commands.

We tested each of the Limit Switches with the continuity setting of the Volt Meter and we are confident they all show OPEN until triggered.

They should all be connected to the correct ports on the machine.

I’m a new Member so I can only attach 1 image and not share a link, So I’ve copied the text from the images.

Image 1: (SwitchesOPEN) We tested the Limit switches using M119 and we are getting a mix of OPEN and TRIGGERED.
y_min: open
y2_min: open
z_max: TRIGGERED
z2_max: open
z_ probe: TRIGGERED
ok
ok T: 0
ok T: 0

Image 2: (SwitchesTRIGGERED) We then Pushed and held all 5 limit switches and tested M119 again, Here is what we got.

Đś119
Reporting endstop status
x_min: open
ĐŁ_min: open
y2_min: open
z_max: TRIGGERED
z2_max: open
z_probe: TRIGGERED
ok
ok T: 0

What I’m seeing online is a possible Firmware issue. But since the Firmware was Pre-Loaded when I ordered it from the V1 Shop, I’m hesitant to re-flash the firmware. I expected it would be configured correctly? But I don’t see how it could be a Hardware issue.

Board is the SKR Pro1.2, 5x 2209 drivers, TFT35 E3 V3 -flashed-.

Would love any help. Thanks!

2

@vicious1 Thank You for being willing to help.

3

The switches are only active during homing, they are not active any other time (you can change that but it is not recommended).

4

Looks like your z and probe might be wired backwards.

Try the Jackpot CNC Controller - V1 Engineering Documentation in the terminal in the webui.

6

@vicious1 I know that the Limit switches are only active during Homing. Does Homing only take place when GCode is uploaded and the machine is running? We assumed when we use the Touch Screen to HOME the axes, that the Limit Switches would be functional to HOME the machine to 0.

There is no Z_Probe TouchPlate connected yet.

7

yes.

Follow The link I gave you to use the $Limit test.

8

@vicious1 The $Limit test responds with repeating “ok T:0”
Unfortunately, I don’t have the JackPot board. I thought it would be nice to have the Touch Screen so I unknowingly ordered the SKR Board for the LRV4, I did not realize this was not the recommended board when placing the order. At this point, Should I cut my losses and order the JackPot Board? That would also keep me from having to cut and replace all these wire ends that do not securely fit onto the connectors on the board.

Is this why I’m having problems with this Standard Config because I did not order the correct board?

9

OHHHHHHHHHHHHHHhhhhhh, that makes more sense now. Sorry I skimmed over the m119 part.

The SKR is perfectly fine for the LR.

Use M119 and test each endstop. One at a time. You need to keep it triggered and run M119, make sure each one changes between open and triggered.

If it does not change you need to check your wiring. If you ever plugged that endstop port in wrong it could have shorted out that pin and permanently damaged it. (the main reason I suggest the jackpot, I took out the power pins near the signals).

10

That makes sense, if your z0 endstop is showing as triggered when you home it’s stopping immediately. Check your wiring for that endstop.

11

Endstops should be wired normally closed. So they should be a closed circuit when not triggered and an open circuit when they are triggered. The language of M119 is confusing.

This shows z_max has a wiring issue. The z_probe is wired normally open, so this is actually shorted to ground somehow.

None of them changed. So that doesn’t make any sense. Are you sure this is what you got?

I would appreciate a picture of the controller wiring to make sure we don’t have any obvious wiring mistakes.

1 Like
12

It’s been a few days, I’ve been using the machine quite a bit and have a pretty good understanding of it at this point. I couldn’t get those Limit switches to do what I thought they should based on my experience with how 3D printers act. So I just started using the machine with my own Zero set. I saw a comment from one of you elsewhere that you said no one really uses the limit switches with this machine. I’ve been manually pushing the Y axis to mechanical 0 to physically confirm the axis is even. Then I’m “Moving” the machine to where I want it to start in the corner of my 4x8ft sheet of wood. Then the G-Code automatically sets that point as Zero when the code starts.

The Limit Switches are still a bit of a mystery to me, It would be nice if it could automatically run into each switch (Like a 3D Printer) so I could use absolute Home for when I need to Re-Cut something or just want more precision. But it works to set my Zero and then run the code.

I’m going to setup a couple of relays this week to turn on and off the Router and vacuum system. Plus connect a Rasberry Pie with a Camera so I can remotely monitor it as it cuts larger stuff.

13

The point of homing Y and Z with dual endstops is to square the gantry of the machine and ensure its planar to the work.

1 Like
14

We all use them. Dreyfus nailed this one.

This is exactly how they should work. Have you looked through the milling basics page?

Please, please never walk away from your machine. Fire happens in seconds. You have a 1/4hp router with a fan on it blowing directly at the firey point. If something happens you have a rather large fire before you can get to the E-stop let alone back inot the room.

15

This is a spectacularly bad idea. Unless you are heavily insured and are looking for a way to burn your house down with plausible deniability…

16

Sorry if this feels like piling on, but I’ll repeat what others have already said.

You’re operating a computer controlled murder robot and fire starting machine. The ability for things to go horribly, horribly wrong with one of these is measured in mere seconds.

Please do not operate your machine remotely. This is a very, very bad idea.
If nothing else, your property and casualty insurance provider will thank you.

17

I’ve had success with cutting smaller pieces, but am having issues with Alignment and the machine going rogue when cutting 4x8 sheets. Our 2 LowRider carriage rails are 5ft each, and the main rail is 10ft. The belts are not too taut, I don’t think they are slipping when cutting. I’m also pretty sure there is nothing getting caught or snagged stopping it. It was better the other day before I cut and added the stiffeners, but I had not yet cut something full 4x8ft. Now with the stiffeners in, I’ve loosened those to try and better realign before tightening things back up.

Please watch this 3min video, to the end where the main issue is.
https://youtu.be/mC_SFyMTdH8

I appreciate your encouragement that I should not walk away from the machine.

18

It looks like you’re either skipping steps or have loose grub screws on the X axis stepper.

2 Likes
19

Is your vac hose grounded?

21

It is now, I had forgotten to do that. I grounded the hose to a spot on the Dust Collector which I’m pretty sure is grounded to the grid.

22

That should help.