New Pololu DRV8825 Stepper Motor Driver: A4988-compatible with more power!

so am i correct now to assume that these drivers will drop in to a ramps? im building a new printer which uses two motors per axis 0.85A each so in parallel it would be 1.7A, I think these will probably work better than the standard A4988 that i have already. plus the extra microstepping is a plus, although to be honest the steps are so small already with my 15 tooth gt2 pulleys that I doubt i would even notice a difference. although now i could run 36 tooth pulleys with about the same accuracy and tremendous speed.

Hi, aduy.

Most likely yes. The microstepping settings are different, which probably requires some kind of reconfiguration. Please refer to the differences at the bottom of the DRV8825 product page.

- Ryan

Hey,

Has Pololu released any gerbers or BOM for their boards?

Also why does one site say Kliment designed it?
[www.reprapdiscount.com]

Edited 1 time(s). Last edit at 05/22/2013 12:23PM by Simba.

Hello, Simba.

No, we have not released our board fabrication information. The schematics are available on the product webpages. The board you link to is different from our DRV8825 carrier and is not designed by or affiliated with Pololu.

- Ryan

Hello,

I have an issue with DVR 8825 (older version were extra resistor is required. I am placing it on RAMPS 1.4 with stepper motor NEMO 17, 0.9deg. . But at first I have soldered the resistor to Reset - Fault. I noticed it after I had no respons from the 3D printer. I corrected the mistake but result was the same - no respons. Could it damage the ship? The issue is in stepstick because with ordinary ramps stepdisks everything works.

Many thanks in advance!

Hi everyones.
I use my 3dprinter on drv8825.
Works on ramps 1.4 whitout any problem.

Except max speed 60mm/s. If I turn 100 or 120mm/s. It stops.
But it because arduino have 16Mhz off speed.

photos of printed parts)
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If link not works. reprap group
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face book. Aleksandr Mustafaev posts.

Is the pull-up resistor on the sleep pin still necessary?

Currently I am using A4988 stepper driver with my RAMPS 1.4 board. As I know Ramps 1.4 support max 1/16 micro stepping through firmware jumper settings.

Also I am using Merlin firmware to control my 3d printer.

Somebody can advise me how to use DRV8825 step drivers for RAMPS 1.4 broad with 1/32 micro stepping really appreciate.

Plain and simple, just replace the A4988-based by the 8825-based one, touch no jumpers and you have it.

Please note that because you now have 1/32 microstepping you will need to adjust this axis calibration value (times 2).

Thanks Misan.

If I am correct I should double the values for axis calibration values to achieve 1/32 micro steps.

In Merlin firmware, configuration.h file having following default settings for 1/16 micro stepping settings.

########################################################################################
// default settings

#define DEFAULT_AXIS_STEPS_PER_UNIT {78.7402,78.7402,200.0*8/3,760*1.1} // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {9000,9000,100,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for retracts
########################################################################################

Please advise me how to change values for 1/32 micro-step settings. I am not good in Maths to calculate these values.

You just need to add *2 in those axis you change the driver:

#define DEFAULT_AXIS_STEPS_PER_UNIT {78.7402*2,78.7402*2,2*200.0*8/3,2*760*1.1} // default steps per unit for Ultimaker

I am trying these drivers but my motors are making an unbearable noise when they are holding torque without moving. And when they move, the movement is not smooth.

Hola misan
siguiendo el metodo de medición por V ( 1v = a 250mA ) en estos dvr8825 cuan seria la medición ?
ya que la escala cambia 1.6mv a 2.6mv al girar el pote

According to this page: [www.pololu.com]

Current limit (A) = Vref x 2 so 0.5V will mean 1A and 1V will mean 2A (you do not want to go that far most likely, unless you have additional cooling). Max value could be 0.8V (or 1.6A) or a bit less (without a cooling fan).

I just got 5 of these to replace my a4988 drivers in my audrino, ramps 1.4 using marlin. I replaced the z axis only and what i noticed is that all the a4988 drivers work untill you try to move the z axis with the drv8825 then nothing works even the z axis. I then added the 4.7k resistor on the sleep and fault pin, still the same result. Then I pulled the three jumpers under the z axis, still the same thing. WHAT AM I MISSING? any help would be appriciated.

psi,
this is an issue concerning your Marlin firmware. The timing pulse is to short and you have no configuration possibilities to change this. Look here. If you change your firmware to Repetier you can change the "STEPPER_HIGH_DELAY" value

greets Don