Run a second gcode file without homing after first gcode file?

jay_s_uk

@mrehorstdmd why not just not turn the motors off after the first?

mrehorstdmd

@jay_s_uk That doesn't help. If you don't home the axes at the start of a new file, you get error messages and the table won't run.

cosmowave

@mrehorstdmd What's in your start.g?

jay_s_uk

@mrehorstdmd i can run more than one file on my printers without having to home in between.
I've just ran a test file with a couple of movements multiple times and not needed to home

bot

Ensure your end gcode doesn't shut off the motors, and you could do print after print non stop.

There is nothing preventing the machine from printing again after a print completes. Any homed state was commanded by the user-provided gcode.

deckingman

@mrehorstdmd M564 H0 might be what you need. I have it at the end of my config.g because I'm always playing around and having to home axes first can be a PITA. It certainly allows one to jog axes around without them having been homed first. The only thing I'm not sure about is if something special happens when printing from an SD card. It'll be easy enough to send M564 H0 from the console to test it out. https://duet3d.dozuki.com/Wiki/M564

fcwilt

@mrehorstdmd

There is no requirement to home your printer before starting a print but in most cases it is the safe thing to do.

But whatever is homing your printer is under your control.

Either the code generated by the slicer or code that you have created to be executed at the start of a print is doing the homing.

You could create a global boolean variable that controlled if homing was done and one or two macros to set the state of the variable.

Or you could use an M291 to query if homing should be done.

Frederick

mrehorstdmd

Thanks for the replies. I'll check the the config files and try a few experiments tonight.

dc42

@mrehorstdmd most likely your slicer is adding a M18 or M84 command at the end of the generated GCode file. That will turn off current to the motors and flag them as not homed.

mendenmh

When I am running 'mass production', such as when I was doing repeat prints of PPE a year ago, I never re-homed the printer for a month. If you don't turn off the motors, it should be fine.

mrehorstdmd

@dc42 I think that's it. I append M18 commands to the ends of files to kill the noise that the motors make when they are idle. I'll try running without the M18 commands.

fcwilt

@mrehorstdmd said in Run a second gcode file without homing after first gcode file?:

@dc42 I think that's it. I append M18 commands to the ends of files to kill the noise that the motors make when they are idle. I'll try running without the M18 commands.

I've heard others doing the same.

I wonder why that happens as the fans on the power supplies of my printers mask any noise the steppers may be making.

What sort of noise are you hearing?

Thanks.

Frederick

sinned6915

@mrehorstdmd might you be able to just reduce the current to a very low value instead of off with M906 ?

mrehorstdmd

@sinned6915 I'm using integrated servomotors, so there's no firmware control of the idle current. They make the usual hissy/whiny sounds that steppers make when they're idle. There are no fans in the machine- it's a sand table that sits in my livingroom, so it needs to be as quiet as possible. You can see/hear it operating here.

@fcwilt @dc42 Yes, it was the M18 commands at the ends of the files that were preventing running a new file.

T3P3Tony

@mrehorstdmd if you want to turn off the motors, but have the patterns work as you expect then you will need to use G92 to set the position of the axis. Of course if there is any movement of the axis under the table while the motors are off then you could crash into the axis limits as the pattern gets to the edges....

fcwilt

@mrehorstdmd

Very neat.

Frederick