Endstops

Through the menu on the ramps board I am able to move the Z axis down, but not back up. It says something about the endstops. I don’t have any endstop switches wired to the ramps board. Should I? Is this something I need to change in the firmware?

Thanks for your help.

Ryan

If you are using my standard firmware, it should work with no endstops. If it doesn’t you have a short on your z min pin somewhere.

If that isn’t the case more info please.

Can you run an M119 from a console? That will tell you which endstop it thinks is triggered. You might have to invert the logic or enable a pull-up. What firmware do you have on there?

It seems to be software triggering the endstop. The ramps thinks the XYZ coordinates are all zero when its first turned on. I can move it in a positive direction and everything is fine. If I try to go to a Z position less than zero it throws a Z endstop error.

There doesn’t seem to be anything wrong with the hardware. I guess I don’t have this setup properly. I’m not quite understanding what coordinates it expects to start at.

 

I’m using this firmware. MPCNC813_GLCD_EB

If you’re using repetier to move your cnc, go to config, printer settings, printer shape. Under the Printer type drop down make sure you’re selecting cnc router. Otherwise it won’t allow negative movements.

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I wonder if that is what I was encountering this weekend with my laser cutting test. If I set the origin in Fusion CAM as center of workpiece, it would only do the quadrant above and to the right, other than that it just made a line up and down the X & Y axis from the beginning. When I switched origin to lower left of workpiece, it worked fine. I’ll have to check that in repetier when I get home.

Dang, do I need to add that to the instructions? I don’t remember needing that. I’ll have to plug one in and check.

Not sure if my issue was related to repetier, dual endstops or something else. I wouldn’t vote change anything yet, I will adjust the setting in repetier and try to re-run the gcode I was having trouble with sometime in the next couple of days.

Dual endstops? That is different, then that means you wired them NO instead of NC.

I will confirm but I’m pretty sure they are NC per the instruction page. I’m thinking that with the dual endstop firmware, it just won’ t drive to negative coordinates because it assumes (maybe not the right word) that after G92 X0 Y0 that it shouldn’t go negative from there since that should be the endstop. (I was actually just issuing a manual G92 out in the middle of the machine since I was just testing, not actually doing a home command.) The gcode looked good and the simulation ran properly in camotics and show travel looked correct in repetier. (Below is the little doodle I was cutting just to see how well the laser would cut.) If I had center of part selected as origin, when it went to cut, it should have started in the NW quadrant, but it just moved up and down along the left side, then for the SW quadrant it just seemed to skip that and the SE quadrant just went left and right along the bottom, then the NE quadrant cut correctly. Once I switched to lower left of the part in CAM for origin, it all cut fine. A bit of an oddity, and something I am going to try to cypher out, but not a big issue as everything works fine so long as I stayed in positive X & Y coords.

[attachment file=51092]

I knew that the software endstops will keep the machine from travelling in the negative direction, past the endstops, but I’m not sure if the G92 actually changes those limits. What you’re saying makes perfect sense though, the software endstops are keeping the machine from driving into the negative.

I wonder if the soft stops are worth the trouble. If you smash into the endstops, will the machine break anything? The machine might need a new cal if the stops moved, but what other consequences would there be? Just thinking out loud.

Didn’t it used to be? I can’t remember. I know when I first started with these things, Repetier didn’t have cnc as an option, but it did have a checkbox to allow negative movements.

You can easily test if it’s repetier or the firmware by homing, moving to the middle G92 zeroing it, then G01 X-10. If it moves into the negative, then it’s repetier filtering things, if it’s the firmware, it won’t move, and nothing in repetier will help.

With endstops enabled there is no negative XY movements, you can change that in the firmware. You should be using work offsets not really changing your Zero. So you home to XYmins, and tell it where to start the project, this is one of the reasons I do not ship or recommend end stops until you absolutely need them. It is an extra step.

Try moving the object in the CAM, not manually setting a Zero see if that fixes everything.

Quick question regarding the end stops, with the complete wiring kit/Rambo dual board that is sold is really only 2 micro switches needed? I just got my MPCNC all together yesterday and started to play with the X/Y/Z and and noticed that gcode command M119 has 4 instead of 2? (X/Y min & max).

If I use a jumper and short out the two other X/Y max pins then M119 returns all 4 open and I can move the unit in any position I want.

Question is, does the dual endstop kit only come with 2 micro switches and is there an easy way to just turn it off on the firmware or just reflash?

Thanks!

Jason

 

 

4 are needed and generally a z axis touch plate as well.

If you do not want to use the dual endstop you either need to wire them up and not use “G28” or do not wire them up and re-flash the standard firmware.

any recommendations or good links on a touch plate? There’s tons out there. Also, do you sell additional switches for the end stops? I didn’t see any on your site.

 

Thanks!

The z depends on your use, some wires an alligator clip and a thin piece of metal is kinda the standard.