RAMPS jumpers and microstepping

I am new writing a question, but I always read the forum. First, I want to thank everyone that contributes sharing experiences and knowledge to this place.

I have tried to take some pics to show my doubts. the problem begins when I am preparing the stepmotor to move around the axis. It makes tiny movements, like fast and little increments. All 4 stepdrivers are set to Vref= 0.5V.

I need to use full step. So I pulled out all jumpers in x, y, z axis.

Fullstep
Pitch = 4mm
Unit per step = (200/4) = 50

I don´t know if the problem lies in the formula, or acceleration, or speed. I have tested the drivers, all working properly.

That looks good.

I cant see a question here

vref is related to you stepper motors and drivers, wich you havent listed any details for your stepper motors (and they look tiny, but could be big machine)


I also have to ask why you have to use full steps, that just uses so much more power is jerky and loud.

Some Ramps clones have bridges under the jumper pins. No matter if the jumpers are on or not, the stepper would run 1/16 anyways.
-Olaf

Quote
Dust
That looks good.

I cant see a question here

vref is related to you stepper motors and drivers, wich you havent listed any details for your stepper motors (and they look tiny, but could be big machine)


I also have to ask why you have to use full steps, that just uses so much more power is jerky and loud.

Sorry, the steppers are: NEMA17 42BYGHW609 (x, y and z axis) , NEMA 17HS4218 (extruder)

I am facing trouble in getting the right step per unit and printer axis displacement relation. No matter what I do, I get wrong relations, or steppers just not move. Do you have some idea on that issue?

I may be wrong, someone can correct me later. I have SFU1204 ballscrews (D=12mm, Pitch= 4mm), so, if I operate at 1/16 microstepping, considering NEMA having 200 pulses per rotation, each 3200 pulses per second, I get only 4mm/s. If I operate at full step mode, the same 3200 pulses per second can give me 64mm/s.

I have bought a extruder, rated at 2.5 inch/s max extrusion speed with 0.3 mm nozzle diameter. It gives about 63.5mm/s extrusion max speed wich is close to 64mm/s max speed axis displacement operating at full step mode.

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o_lampe
Some Ramps clones have bridges under the jumper pins. No matter if the jumpers are on or not, the stepper would run 1/16 anyways.
-Olaf

Olaf,I didn´t know that. How could I see that? Does short-circuit checking with multimeter?

Yes. turn off power supplies (unplug usb also) . pull jumper. check resitance between pins where the jumper would sit. Should be high. A low indicates there is a hidden track shorting it.

Edited 2 time(s). Last edit at 08/22/2015 01:23AM by Dust.

"each 3200 pulses per second, I get only 4mm/s"

standard ramps can do ~67000 max step per second....

if you looks at [reprap.org] you can caculate the steps its using, using quad stepping mode (wich is the default)

Quote
Dust
"each 3200 pulses per second, I get only 4mm/s"

standard ramps can do ~67000 max step per second....

if you looks at [reprap.org] you can caculate the steps its using, using quad stepping mode (wich is the default)

Great info! I thought RAMPS were unable to reach that pulse rates. Really useful site you have posted above. I will keep reading.

Quote
Dust
Yes. turn off power supplies (unplug usb also) . pull jumper. check resitance between pins where the jumper would sit. Should be high. A low indicates there is a hidden track shorting it.

OK. I did. All tracks seems ok

Quote
dremel

Quote
Dust
That looks good.

I cant see a question here

vref is related to you stepper motors and drivers, wich you havent listed any details for your stepper motors (and they look tiny, but could be big machine)


I also have to ask why you have to use full steps, that just uses so much more power is jerky and loud.

Sorry, the steppers are: NEMA17 42BYGHW609 (x, y and z axis) , NEMA 17HS4218 (extruder)

I am facing trouble in getting the right step per unit and printer axis displacement relation. No matter what I do, I get wrong relations, or steppers just not move. Do you have some idea on that issue?

I may be wrong, someone can correct me later. I have SFU1204 ballscrews (D=12mm, Pitch= 4mm), so, if I operate at 1/16 microstepping, considering NEMA having 200 pulses per rotation, each 3200 pulses per second, I get only 4mm/s. If I operate at full step mode, the same 3200 pulses per second can give me 64mm/s.

I have bought a extruder, rated at 2.5 inch/s max extrusion speed with 0.3 mm nozzle diameter. It gives about 63.5mm/s extrusion max speed wich is close to 64mm/s max speed axis displacement operating at full step mode.

It's called steps pr second. Not pulses. Just to avoid confusion.
When operating the printer you do not tell it to use X steps pr second. You tell it to move X mm/sec and the firmware Will match the the desired speed with the steps Needed.
You always want to use max multistepping possible for your setup.