New to forum and ramps / motors switching off issue

Hi

Im most of the way through a delta printer build with ramps 1.4 with lcd, genuine pololou drivers (with heatsinks) and nema17 motors

in general its working ok, just sorting out calibration at the moment, but I've come accross an issue i cant seem to find an answer to searching the web, so here i am asking the experts / community directly

If i home the motors or leave them in one position for about a min or 2, all 3 motors turn off and the print head comes down to rest on the bed, obviously when i'm doing a print and it finishes / homes at the end (without the motor off command at the end) i dont want the print head to crash into the print its just finshed

the stepper drivers are not getting too hot to touch, and the motors are warm but not hot

any ideas of what might be causing this, does not look like a heat cutout, but time based ... I have to admit, I've not timed it to see if its always the same length of time

many thanks in advance
Phil

sorry forgot to add, im running marlin on the arduino
cheers
Phil

There's a setting in Marlin that controls how long the steppers will stay energized while idle. I can't find where that setting is at the moment, but maybe someone else can chime in.

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My motors shut off all the time while waiting for heaters to come up to temperature prior to the print starting. It's no big deal because I rehome after I reach temperature via my start g code. In my case, I only ever see movement in the X and Y axes. I can't see how the Z axis would move as it's driver by a screw which resists motion in reverse (the screw can move the nut, but the nut can't turn the screw).

As far as after the print - why are you leaving the head near the print where it can melt things anyway. I have end gcode that moves the head up a few millimeters and to the left rear of the print volume.

And yes - as stated, there is an idle timer in marlin - in Configuration.h - where you can specify the amount of time the motors will remain idle before they power-down.

Edited 1 time(s). Last edit at 11/06/2013 10:34AM by jbernardis.

Hi

thanks for the info, I'll look to see if i can find the timeout and increase, would be great if there was a park facility you could invoke on time out.

of course at the end of a print i would want to move the head to a safe place, but with it being a delta printer and not a normal type, it uses the motors to keep the print head aloft and clear of the work, I dont want to teach anyone to suck eggs, but if you google rostock, thats the style i've built, and gravity will overcome the drive belts and the print head will move down when the motors are not powered

Thanks again
Phil

excellent, found it, it was in the advanced config section, set it to 20mins, thats enough leaway for either the print and hotend to cool, or get to it before it turns the steppers off

Thank you for your help
Phil