Center point home

[mauriceman]

Currently using V1.3j and grbl_11c2.hex. I can't seem to use the center as home anymore. It always defaults to bottom/left. Say I send a dxf of a single 25mm x 25mm box. If I define 0,0 on the laser screen (right click home button) no matter which I select on the main screen for center (absolute) or not, it always defaults to bottom left home. If I reload a previous version (say 1.3e) I can start from the center and have it draw around that point. Am I missing a setting?

I also used to have the laser come on with low power when jogging. That was nice to locate the start center on my work piece. The laser doesn't come on anymore unless I set a very low power then manually turn on the laser. Again, am I missing something here or was this just a fluke for my particular setup?

Thank you all

[Zax]

Interesting, anyone else have problems with 1.3j and 1.1c2 firmware?

I'm using the same setup and center start works fine, with or without absolute checked. You are clicking the "Home" icon at the center and the machine is heading off back to the lower left when you start the G-Code?

The laser staying on at low level was a bug in J-Tech 0.9g firmware, which it sounds like you were exploiting. Based on several user requests I added a "workaround" in T2Laser to prevent it (as it could be considered a safety issue). You may be able to trick Grbl 1.1 into the same result by setting min PWM speed ($31) to your low light setting, but after M05 it may not work.

[mauriceman]

The machine never moves to a lower left position when home (0,0) is established and sent gcode. This new home (0,0) that I set becomes the lower left corner of the burn but I can't seem to get my artwork to burn centered around this new home. It always goes to the upper right and burns the image, then returns back to the home I set. What are the new presets on the laser screen for (Machine Home, Load Position, Use machine Positions)? I'm doing a lot of smaller round objects with circular artwork so centering (at least for me) is important,

I can see the safety issue regarding jog/laser that I exploited. Gotta find a new work around, I guess.

I will say, having PWM is going to be nice but this new laser has a 9mm Nichia diode (supposedly) and it's spot is slightly elongated. I have to soften the focus a tad to burn horizontally and vertically equal widths.

As always, Thanks

[Zax]

Well it appear I need to re-work my center start code as adding the absolute option has caused multiple "side effects" of the unwanted variety. I still can't replicate what you are seeing but will be doing more investigation and testing once I correct things.

The preset locations are for you to set as needed, if you have home switches they are more useful but can still be used. I just put some examples in there, the first goes to the machine 0,0 position regardless of where the home positions are set.

Hang on, that made me think of something. You are using Workpiece Home and not the new Machine Home?

So back to presets, you can set and then go-to a position in either the workpiece or machine coordinate space. Set the laser to a point and right click on one of the preset slots, enter a name and it is stored. Click the name and it will go to that point (if you hover over the name it will show the positions that have been stored).

[Agastar]

Well it appear I need to re-work my center start code as adding the absolute option has caused multiple "side effects" of the unwanted variety.

Some call those unwanted features, I call them bugs LOL.

[ggallant571]

Don't do anything and someone will do something that replies on the current incorrect behavior. Then when you do "fix" it there will be another fury of complaints.

[Agastar]

lol, so true

[mauriceman]

OK, this should give everyone an idea what's happening. No matter what I try, can't seem to coerce center home. I can just reinstall an older version. No biggie. Take your time.

[Zax]

I'd like to hear from anyone else using center start and seeing this behavior so we can determine what causes it, as I am unable to replicate it (and believe me I've tried, every possible way I can think of).

The other issue that was reported (related to not using center start) is repeatable and has been fixed but this one is confusing me.

[mauriceman]

Tomorrow, I'll reinstall the software, reflash the nano and try using several of my dxfs that behaved properly before installing the new version. It still could be me doing something screwed up. Maybe it's the curse of Medicare which I go on in November (yea, I'm old).

Thanks again

[ggallant571]

Bring your laser cutter to the Medicare office. Hold the agents hand under the laser. Ask them to do something simple. When they fail turn on laser and cut off one finger. Don't worry about the blood or screaming. Now ask again for something slightly more difficult and repeat the laser procedure. Usually it only take about 4 fingers before you get your name spelled correctly on their system.

There are a couple of fingerless, toeless, eyeless employees at the local office but that was before mu time.

[Zax]

I'm not doubting you, it's probably just a combination of settings I've yet to try. You mentioned DXF, do you have any of the settings enabled, relocate origin or optimizer?

I probably need to go test some of those as I was doing images, Sketch, Sketch plus and trace but also checked DXF's quickly.

[ROSS]

Maybe it's the curse of Medicare which I go on in November (yea, I'm old).

You are now on course where everything gets worse!!  Join the gang.  (LOL)

[mauriceman]

Mystery solved. It was my oldtimers kicking in. I didn't realize that on the drop down menu both the first menu items could be checked and the fly-out items could also be checked. I was only checking the absolute item and not the primary centering one. That seems to be a little counter-intuitive from what I'm used to menu structure wise. So what does the absolute second item do?

Is there newer documentation explaining all these new features out there yet?

Again, thanks for your patience and assistance.

[Zax]

Arrh! That makes sense, great so there's not a hidden bug. If you only have absolute selected it does nothing, If you want it to work like before leave that unchecked and just use the center start option.

Documentation is now within T2Laser, press Shift-F1 or select Manual from the Help menu.

Then you can easily search it, so for example, "absolute" brings you to this:

Center (Start Point)

o   Position the laser (and set home) in the center of the job (between extents) before starting
o   Absolute option uses the entire drawing from 0,0 to maximum extents for center position

So what does that mean, well previously I would take the extents of the drawing... min and max, then figure out the center by min + ((max - min)/2) but if you select absolute it will use 0 to max (or max/2).

e.g. for a drawing that starts at 50,50 and goes to 100,100. Center start alone would place the center at 75,75 but selecting absolute would place it at 50,50. This is also important when using the frame feature as one will frame 50,50 to 100,100 and the other 0,0 to 100,100. Big difference. As many features are, this was a user request.