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X and Y move, Z dosen't move, limits won't trip.

Posted by whatisacnc 
X and Y move, Z dosen't move, limits won't trip.
May 19, 2013 12:55PM
Hi everyone,

New problem today... I have X and Y moving nice but the Z axis just jumps back and forth/ chatters when I try to move it in Pronterface, the extruder motor seems to be working nice too, it moves 5mm filament in when I click on the "extrude" 5mm in Pronterface. When I try to move X or Y and I trip the opto nothing changes, the bed or extruder will just keep moving.

I've tried another step-stick in place of another for the z motor and same problem, this is the Sanguinololu rev 1.3 with two headers, but I'm only using one, do I need to use both?

Thanks in advance for any and all help,

Rob


[whatisacnc.com]
Re: X and Y move, Z dosen't move, limits won't trip.
May 19, 2013 01:34PM
I've pulled out the multi-meter and I checked the continuity of the wires, there's no issue on that front, then I disconnected one motor and found that the motor's trying to move but has little torque, it's the amperage I think.

I'm using a 12v 300w power supply with Nema-17 .9deg 2.4A stepper motors from Phidgets. Are they too big for this driver?

Any help is truly appreciated, I'm really lost for options and I'm sure it's something I'm not setting up properly.

I've tried moving the pot with no luck, it did prove that the motor is trying but just not getting the juice it needs.

Thanks again for all the time and help,

Rob


[whatisacnc.com]
Re: X and Y move, Z dosen't move, limits won't trip.
May 19, 2013 01:37PM
What does issuing command "M119" return for the end stop values?

Fl0yd
Re: X and Y move, Z dosen't move, limits won't trip.
May 19, 2013 01:58PM
Thanks for getting back to me.

I haven't tried to issue that command and I don't know how. Do I use Pronterface?

Also I even disconnected a wire to my Y axis and it still moves, it's not supposed to right?
Re: X and Y move, Z dosen't move, limits won't trip.
May 19, 2013 08:54PM
Those motors are drawing 5amps between them. (I assume you have 2) Standard pololus or step sticks are really not meant to handle even one of those. My 23s only draw 2 amps each. You need a 6064 and, with 5 amps, I'd contact the seller and verify the suitability. [www.massmind.org] .(I'm NOT the salesman for these, I just keep seeing folks with high amp motors todayeye rolling smiley) If this doesn't pan out, Sparkfun has nema 17 .9deg mots that are a whole lot less power hungry. You have to keep in mind that unlike other types of motors, steppers are constantly under power, and will overcome their current drivers capacity in short order, when drawing that much more amperage.
Re: X and Y move, Z dosen't move, limits won't trip.
May 21, 2013 10:22AM
whatisacnc, the method of issuing commands in Pronterface is to type the required command - in this case m119 - into the textbox at the lower right hand side of the window and then click the "send" button. The results should be displayed in the main window above that. Assuming conventional witing of your endstop switches (and assuming that they're mechanical switches like mine, rather than optos), when none of the switches are activated (ie with everything in its centre positions, away from the stops), your results should be something along the lines of X:L, Y:L, Z:L which indicates that the (normally-closed) switches are connecting the input sensor line to the ground).

You can check the operation of your switches individually like this;

With the machine centred, type m119 into the box and click Send (pressing Enter works on most softwares too)
Result will probably be X:L, Y:L, Z:L

Now operate the X endstop switch by hand and type the command again
This time your result will probably be X:H, Y:L, Z:L

Now try with the Y endstop and the Y result should be H while the others are L and so on.

At least that's the way it works on my Prusa Mendel I2 (now that I've finally got the endstops working right)

Of course if you are using a different type of printer then your results may well be different, but ultimately you can still use the m119 command to read the status of all three of the switches.

Good luck with this
Re: X and Y move, Z dosen't move, limits won't trip.
May 21, 2013 12:57PM
If it turns out that the two motors are drawing too much current, you might fix it by wiring them in series.
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