extruder stepper problem

Hi!

I'm assembling a reprap but I have a problem....

I'm using a sanguino with a breakout shield, temperature sensor v2.0 with a 100k termistor, pwm driver v1.1, 4 stepper motor driver v1.2, and the latest firmware (not 5d). the extruder is stepper driven.

when i connect everything, the xyz motors work, but the extruder doesn't. even if everything is off, it starts "pulsing" after a few seconds. It seems to me that the software is not giving the order to the stepper plate... what can i do?

What do you mean by pulsing. If the stepper is wired incorrectly, it will step back and forth one step instead of moving forward on every step. This starts when you turn the extruder on and stops when you turn the extruder off. This behavior also happens if there is too much load on the stepper, such as when there is a filament loaded, but the filament gap is not large enough.

Try connecting a different stepper to the board and see if it turns. You already know your xyz motors are wired correctly, so try one of those.

I connect the extruder stepper plug to the x, y or Z and it works. I've already tested the extruder in that way... the stepper controler also works if i connect the x y or z plug... The problem, i believe, is in the firmware...

the stepper goes back and forth, like you say. It doesn't change wether i turn the extruder on or off. by what i've measured, the enable pin is allways with 10V, I believe this is the reason of the "pulse". its on but it has no other information on where to go, nor direction nor steps. However, no pin turns on or of(measured by the voltimeter) when i turn the extruder stepper on or off. I'm using the 1,2 version of the stepper controler, and i did correct the enable pins on parameters.h (its inverting only on v 2.x and up).It seems to me that its missing the firmware part for controling the extruder stepper...

Surely the enable pin should be no more than 5V?

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[www.hydraraptor.blogspot.com]

You can disconnect the enable wire on the stepper motor driver v1.2, it defaults to enabled.

If you don't have a ground wire between the stepper motor driver and the sanguino, the stepper will take random steps at random times.

The stepper is enabled even when it isn't moving. This basically tells the stepper to "don't move", which is different from "don't do anything" (disabled) because it will be harder to overpower the stepper and make it move with current holding it in place.

The step signal is usually too fast for you to measure with a multi-meter. You need an oscilloscope to see it. That is the only signal that changes when you turn the extruder on and off.

The stepper motor driver v1.2 can overheat and that can cause random steps. Try disconnecting the stepper and just watch the LEDs. If they don't exhibit the same behavior as when the stepper is connected that is a good sign you are overheating. You can reduce the amount of heat created by reducing the current on the potentiometer.

I'm assuming the 10 V on the enable line is a typo. It is supposed to be 5 V. DIR should be either 0 V or 5 V and STEP should be 0 V most of the time with 5 microsecond pulses at 5 V. All these should be relative to GND, which should be connected between the stepper controller and the Sanguino.

take out the motor. measure the resistance across the step and dir leads. if the resistance is lower such as 2-4 ohms and the other is normal, or one is open then it may indicate your motor is damaged. if the resistance is low the motor overheated and the wire coating melted.

I would do two things, if you have current control on your board, set it lower. after that hook up another motor of any kind to see if it works, then addjust current flow where it should be.

if the resistance of both sets of windings are ok, then look at the current settings on your board.

Hope that helps.

When i first installed the software, every stepper started pulsating after a while... until i find out in the code that for the 1.2 controler i had to invert the sign for enable and disable... after doing that, they all stopped pulsating. so, i think that the problem i have with the extruder is the same, the enable is on, and for some reason, the motor starts pulsating. perhaps its a "bug" of the 1.2 version, or something. (It may not be related, but i had some issues with the ground wires... On both machines! never had an opto endstop working... had to use regular contact switches... but if i don't use special switches, where when they're off, the ground contact is on, they randomly turned on, and the machine stopped...)

resuming, i disconnect the enable wire, and the extruder stepper keeps pulsating... but if i connect it to the ground, stops pulsating. and it is 5 v indeed... I measured 10 v before but don't ask me how... the strange part is that when i turn on or off the extruder in the reprap software, nothing happens! no signal changes! at least, from the ones i can measure... i just don't know where to turn to... software or hardware...



p.s. the motor works fine if i connect it to the x stepper controler...

Edited 1 time(s). Last edit at 12/07/2009 08:46PM by Jorge Nunes.

Maybe something is wrong with the stepper controller board. You can disconnect your x stepper controller board and hook the extruder stepper controller board up to the same pins and the x stepper motor. Since you no this setup worked with the other board if it does not work now, you will know it is a faulty stepper controller board.

ok, i did found out why my y axis wasn't moving... one of the pits was cutted in the stepper controler. however, the extruder stepper still doesn't move.... and the board is fine, as i have also connected it to the x controler wires and it moves... so, in terms of hardware, the only thing left to do is check if the plug which goes from the sanguino to the stepper is ok... if it is ok, then i may assume the problem is purelly from software...

Try using the test firmware [dev.www.reprap.org]

Instead of using the pins described in the instructions, change the stepPin and dirPin macros in the test firmware to be the pins your extruder board uses (so that you have the exact same wiring for the test).

If this test works, and the normal firmware doesn't, then your problem must be on the software side, most likely in the firmware.

yeap... the test works fine...


One thing i didn't mention, which may be the problem: I've tried to use the 5d code (1.6 version), but when i choose the thermistor, it displays an error message. So, as i was using gen 2 electronics, i've installed the sanguino 1.4 version... in the code, i can't really understand if it uses the stepper motor for the extruder, but it seemed so... I'll try to find the 1.5 version to see if it makes the motor moves...

thanks



P.S. version 1.5 also gives error when thermistor is chosen... "error: no matching function for call to 'extruder::sample_temperature(byte&)"

Edited 1 time(s). Last edit at 12/08/2009 06:02PM by Jorge Nunes.

problem solved. Thanks for the help!



now i just have to figure out why does the host software stops responding sometimes...

What was the solution?

The host software will stop responding if the firmware resets. It also doesn't respond after you turn the extruder on until the barrel reaches its extrusion temperature.

the solution was so simple... it almost made me think i didn't really had a problem... I took a closer look to the settings of the host software, and just had to put no in the fived setting... as he was working like i was using the 5d firmware, he didn't sent the right signal to sanguino... after that, simply worked perfectly! I mean, almost... the heat dissipating plates are too small... i have to purchase bigger ones and fans tomorrow...

sometimes, i don't know why (and also happend in the previous versions), the host stops responding when i'm producing the g_code from the stl... any computer i've used does that... even when sanguino (or arduino) were not connected... It's annoying because you are producing your perfect part, and the software just stops.... and its not a matter of time, i left the pc once working during nightime, and in the morning was still stucked...

don't tell this happens for not having sanguino connected...

Hello,

Did you ever figure out how to get around the error when you try to specify that you will use a thermistor?

Thanks.