Wednesday, January 27, 2010

Wiring up the sherline cnc mill to the controller board

After sitting in various garages around town for the last two years it's finally moving forwards... many thanks to the emc IRC chanel on freenode.

A breakthrough in my understanding and general confidence came at the hands of Andy Pugh who walked me through the laypersons continuity test

Here is the documentation such as it is for the controller card http://greenstonepatent.com/4Axis.pdf
the motors are rated 3.0V, 2A, 1.8 degrees step on the xy axis and 4.5V, 1.4A, and 2 degrees step on the z axis.

I've got a 24V 1A DC power supply handy, as well as a 12V 1A that perhaps I may wire together to get a bit more juice.... still gotta figure that stuff up :)


OK, this will also work: touch motor wires together in pairs and find which pairs make the motor harder to turn.
       andypugh:OK, this will also work: touch motor wires together in pairs and find which pairs make the motor harder to turn.
    andypugh:    You should end up with two sets of three wires
    alidigitalis:    and now we have a red, yellow, and black wire group, and a blue, green, and white group
    alidigitalis:    it should read http://greenstonepatent.com/4Axis.pdf
    andypugh:    Hmm, I am not sure how to tell which is the centre tap. But I would hazard a guess that the white and black wires are the ones.
    alidigitalis:    are those the ones that need to go to the power and ground?
    andypugh:    I think you need a multimeter to tell.
    andypugh:    No, ignore the black and white wires.
    andypugh:    Connect red to A+, Yellow to A-, Blue to B+ and Green to B-
    andypugh:    If you look at the diagram on that link
    andypugh:    It shows that you can use all or half of the coils, by connecting to each end, or to one end and the middle.
    andypugh:    There is another sort of stepper driver where you connect the centre of each coil to earth/ground and then apply the power to one end or the other.
    andypugh:    That is called "Unipolar"
    andypugh:    But you have a bipolar driver, which effectively swaps power and earth as required.
    andypugh:    It doesn't really matter which end of which phase (A or B) you connect to the driver, as long as you make totally sure that you don't connect one phase to another. (I did that, blew my driver).
    andypugh:    ie, make sure that of the two wire families you have seperated, that one set goes to the "A" terminals, and one to "B"
    andypugh:    It is probably worth taking the time to read: http://en.wikipedia.org/wiki/Stepper_motor


anyhow, with thtat cleared up the three axis are now wired... it's time to link up the power cords :)