Problems with stepper motors (SOLVED)

I just got my printer connected with pronterface, I have atmega 2560 with ramps 1.4 and am running marlin firmware. I have gotten the printer to connect with pronterface and I can heat up my heatbed but when I try to move any of the stepper motors I get a shaking bath and fourth and a funny sound that has a almost grinding sound. I noticed in arduino 23 that the baud rate in the serial port is gibberish and also that there is no 250000 that matches the ramps card baud, I have tried switching around different configurations with no sucsess. Also I have used the two sets of pins on the ramps card designated for the z axis stepper motors rather then running the motors in parallel by splicing the wires together, is this a mistake? Any help would be much appreciated, thanks.

Edited 1 time(s). Last edit at 08/25/2012 01:14AM by cmiller.

sounds like the either the stepper drivers (pololus or copies, and who's copies?) need adjustment, or your stepper motors are wired wrong.

To adjust stepper drivers.

Grab a multimeter and with only the usb connected to the board (supplying the logic voltage) adjust the trimmers on the stepper drivers to the appropriate level. If genuine Pololu's measure from the via to the ground as marked red on this picture



adjust the trimmer till its in the ballpark of .4V or 400mV

Some of the copy Pololus use different components so the number may be different for non standard parts. Personally I have the white "non pololus" from redrapdiscount and find my adjustments is around .1V or 100mV.

Put too much power through them and they heat up and shutdown, so if significantly warm and not seeming to do anything give them a chance to cool down.

Once adjusted to the correct ballpark then very small adjustments are all that are needed to get them working optimally.

To check stepper motors are connected properly, disconnect one from the ramps board and check resistance on the 4 pin connector (doesnt matter which end you count from) between pins 1 and 2 resistance = around 2 ohms, same with 3 and 4, between 1 and 3 or 4 open circuit.

GaZ

Edited 1 time(s). Last edit at 08/25/2012 01:34AM by gazob.

Thank you, I did in fact have my wires crossed on the stepper drivers, 4 different colors coming out of my stepper motors and 4 different ones going into the board got me confused I guess, thanks for the help.