Need a clue, Pro5, Opening Up IPS

LordofCandy · February 1, 2024, 6:53pm

I’m at a loss and need a clue.

If the Pro5 is gated naturally at 200ips but Motion allows it to open up to 275ips. What’s governing this in Grbl?

My instinct is to say its $110, $111 & $112:

$110=7000.000 (X-axis maximum rate, mm/min)
$111=7000.000 (Y-axis maximum rate, mm/min)
$112=3000.000 (Z-axis maximum rate, mm/min)

But if that were the case my max IPS is 4.59IPS
in/s= 7000/(60×25.4)

I feel like I’m just stupid because that makes no sense but I can’t seem to pull enough information together to solve for this. Like I mentioned here, I’m not trying to break the machine but I’d like to know the full envelope of potential so I can use the VFD further-- gated really just by the machines ability to push fast enough.

So who’s got a clue and is willing to educate because I obviously need some 'splaining.

SLCJedi · February 1, 2024, 7:14pm

The firmware also has a speed limit we can’t change. So it tops out around 275 IPM.

I’ve just learned to use the rigidity of the machine and replace feed rate with depth of cut to maximize material removal rate.

LordofCandy · February 1, 2024, 7:38pm

So I don’t need to change anything to achieve 275? I’m using gSender, not Motion. I was just confused on what Motion is doing… it can only affect grbl values at the end of the day…

But I love your work around. Just modify the doc to get towards the maximal utility. Still aiming for a chipload of what .003 to .006?

Thanks Josh.

CthulhuLabs · February 1, 2024, 8:04pm

Yeah the XY feed rate is locked at 7000 mm/m:

#define MAX_XY_FEEDRATE 7000.0
#define MAX_Z_FEEDRATE 5000.0

github.com

J-eremy/grbl-shapeoko-5/blob/master/grbl/config.h

/*
  config.h - compile time configuration
  Part of Grbl

  Copyright (c) 2012-2016 Sungeun K. Jeon for Gnea Research LLC
  Copyright (c) 2009-2011 Simen Svale Skogsrud

  Grbl is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Grbl is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
*/

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Even if you change that in code and compile your own you will hit the maximum step rate of the microcontroller. 8bit microcontrollers are not fast. They can only send out so many step pulses per minute. It is why 3D printers have all pretty much moved to 32bit controllers.

LordofCandy · February 1, 2024, 8:18pm

So what I’m hearing is that at maximal current $110-$111 values is what does equate into 275ips. I’ve been there a while and I’m good with that (for now. xD)

I just couldn’t quite grok how the math from mm/s to in/s, where I’m guessing IPS is derived, worked.

in/s = mm/m / 60* 25.4
4.59 = 7000/(60×25.4)

The math isn’t off but my logic surely has to be.

Agreed, 8bit boards are a bygone thought. Moved up in 3dprinters years ago to 32bit SKRs and I still like to run klipper. Not enough room to store a lot, math a lot, or buffer a lot. But for the moment not quite my concern here but I know you’ve been digging on replacing and moving forward so I watch you. hehe!

gsrunion · February 2, 2024, 2:17am

I think you are mixing up the time units. Everything is in mins…… 4.59 inches / second * 60 = 275 inches / min.

LordofCandy · February 2, 2024, 4:33am

oh… you know… I knew it was something simple and I just couldn’t put my finger on it.

Thank you. I’ll see myself out.

system · March 3, 2024, 4:34am

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