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Home speed in RepRap host - how to contro it?

Posted by t3kboi 
Home speed in RepRap host - how to contro it?
September 11, 2010 05:20PM
I have a junkstrap, that has a high gear ratio on my x an y axes , which limits my speed to around 1000 mm/minute.

In the host software - the jog panel pays attention to this setting - but the home buttons do not - pressing home attempts to move all axes at somewhere around 3000 mm.minute - which is bad for my hardware.

Is there anywhere I can adjust the speed behind the home buttons?

Thanks
Re: Home speed in RepRap host - how to contro it?
September 12, 2010 08:03AM
Just a guess, but in the 5D motherboard firmware configuration.h at line 150 you have:

//our maximum feedrates
#define FAST_XY_FEEDRATE 3000.0

Perhaps you can change it there and thus force it to 1000 mm/min?

You can also set the feedrate in the preferences of the RepRap host. Are they ignored as well?
Re: Home speed in RepRap host - how to contro it?
September 14, 2010 09:15AM
You may also need to turn off Accelerations, many repstraps don't like it enabled
Re: Home speed in RepRap host - how to contro it?
September 14, 2010 01:34PM
Quote

[...] Accelerations, many repstraps don't like it enabled

Huh? I've heard of Skeinforge which can't get acceleration sorted in some recent version but other than that I don't see how the usage of acceleration makes a difference between different machines. Are you sure?


Generation 7 Electronics Teacup Firmware RepRap DIY
     
Re: Home speed in RepRap host - how to contro it?
September 15, 2010 08:06AM
Traumflug, t3kboi -

I'm no expert yet but at the start of Calibrating my Repstrap was fine when just jogging 10mm, but when I tried to Home it, then it started to use Acceleration and was not at all happy. So for my setup (and I expect many Repstraps/Junkstraps) I would recomend setting this to constant speed in the main Firmware, then you can tune it to your setup in Reprap host -

You need to change the Firmware (Config.h) to turn off Accelerations -
Towards the bottom of the file -

// Data for acceleration calculations
// Comment out the next line to turn accelerations off
#define ACCELERATION_ON

Change to ACCELERATION_OFF

You will also need to make sure Reprap Host has this set to -1
MaxZAcceleration(mm/mininute/minute)=-1

To Quote the Reprap manual -
"This is the maximum rate at which the machine can accelerate vertically (i.e. in Z). As G Codes are in mm/minute, this is in the rather eccentric unit of mm/minute2. If you want to run at constant speed, or you have RepRap firmware that does not support accelerations, setting this negative will turn off Z accelerations for the whole machine. "

Turning it off worked really well for me, but I plan to look again at Acceleration speed of my Repstrap at some point.
Re: Home speed in RepRap host - how to contro it?
September 22, 2010 04:11PM
Sorry for the long delay - had relatives in town for the last 10 days. confused smiley

So - my results: Changing the maximum XY fastfeedrates worked fine.

Acceleration - works fine on my repstrap (JacqueStrap - ee eez French..)

I set the acceleration start point to about 65% of my max feedrate - machine works well both with acceleration enabled or disabled.

I am tempted to leave it enabled - I figure there is a reason it was implemented..... spinning smiley sticking its tongue out

Thanks for the pointers.
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