Ramps 1.4 with pololu drv8825 instead of pololu a4988?

I am looking to possibly running the drv8825 instead of the a 4988 on a ramp1.4 and wondering if anyone has done it and what changes did you have to make to the firmware for it to work.I am running marlin firmware.I see that there is a slight difference to the use of the wires the vdd for the 4988 is used for fault on the 8825 and it looks like the sleep and reset pins are just jumped on a 4988 where the drv8825 looks like it needs power to those pins?Main reason i would be looking to go with these is the ability to run more power to the stepper motors and still be able to stay cool..I have a few sainsmart ramps v2 boards coming that say they can run either stepper driver .I see that board has four places for a jumper instead of the 3 the ramps 1.4 has..Ideally i would like to run the sainsmart board on 24 volts and use the pololu drv8825 stepper driver to get the maximum power with my setup..Right now i have been using separate tb6560 steppers with the ramps 1.4 to get the power needed for my bigger machines?It could save me a fair amount of money and make wiring the machines alot easier not having to run the separate stepper drivers

Ive just swapped my A4988 for DRV8825's on ramps 1.4.
If you turn them over you can see most of the pins are the same but a few are swapped.
These seem to be just for the jumpers on the ramps board.
My A4988 were jumpered for 1/16 microstepping but the same jumpers on the ramps board gives me the 1/32 microstepping for the DRV8825'S.

Make sure you get them plugged in the right way round.
On my set of DRV8825'S the pot was on the left hand side instead of the right on the A4998.
Obviously you will damage them 8f you get it wrong.

I left the jumpers as they were as i wanted 1/32 microstepping and simply doubled the steps per mm in the marlin firmware and uploaded it to the mega.
No other changes, worked straight away and seemed quieter on my prusa i2.

Gordon

[reprap.org]

Thanks for refering me to that post i did a search on here yesterday and didn't see anything..That is exactly what i was looking for..I will probably never use the 1/32 micro stepping but it is nice to have the ability to do so if i need to ..I am mainly looking for a stepper driver that can handle a 1.8 amp motor running on 24 volts.and still not e on the edge of running hot.. I set my firmware up so each stepper motor has its own stepper driver that helped alot but i want to be able to run some pretty insane feed and accell rates as i am using the machine for cnc plasma,cnc milling and 3d printing..My machines range from 2ft by 2ft up to 5ft by 10ft..So far i have been super happy with the arduino-ramps1.4 electronics. I am able to run at around 800ipm before i start to loose steps so i set the max to 600ipm for the x and y axis and i can get around 300 ipm from the z without loosing steps so i limit the z axis to 150ipm..But i think if i ran 24 volts instead of 12 volts and went with the drv8825 instead of the a4988 i could possibly get 1000ipm out of the machine without loosing steps??

I have no experience with 24V so I can't give you any advice about that. However, please note that the RAMPS 1.4 is not designed for 24V operation, you are in purely experimental territory there with all the risks that entails (fire, electrical shock, etc...)

I would be running them on the sainsmart ramps v2 at 24 volts it is made to run either 12 or 24 volts

Hi all,

I just upgraded to the DRV8825 on my Ramps 1.4 on a prusa i3 running Marlin. The motors run fine (and very quiet). Move left and right, up and down. Extruder works fine. I have one issue though. They are only moving 1/2 of what the regular steppers did. Meaning 200, 200 is the center of the bed. I changed this in my congfiguration.h file but it doesnt make a difference.

#define DEFAULT_AXIS_STEPS_PER_UNIT {80*2,80*2,4000*2,97.91*2}

Is there another setting to change somewhere in Marlin? I'm stumped.

Thanks
-Kevin

FIXED: Updating for other poor souls who may have this issue. If you have EPROM activated in Marlin, you have to update it with the new settings. If you don't you be stepping at your last setting of 1/16.

Edited 4 time(s). Last edit at 04/10/2015 07:24PM by krwynn.