Stepper Motors

Dave

Anyone have any experience with setting up a stepper motor with a driver control chip. I'm having terrible trouble getting the bloody thing working.

themole

ya, i used one before.

Should not be much to it.

Just read the chip specs to see how to wire it to the motor. Then look at the control pins on the chip. There is usually a few setting pins, and then there is on that you pulse to get the motor to step.

What specific problem are you having?

If you post the exact chip and motor you are using i might be able to give you some pointers.

Dave

The driver is an Easy Step 3000 and the motor is an RS Components 440 442, hybrid uni polar motor. The thing is the stepper motor has 8 wires and the driver has 6 inputs. Now I know the wires to connect to the same input thing but it's just not working, nothing's happening. I've tried tech support for both the driver chip and the motor, and nada.

themole

RS stock number :440 442

From the data sheet on the radionics site you can see the wire colours and the letter which corresponds to them. These then refer to diagrams 2 and 3 in the pdf.

Here is the data sheet for the driver chip.

You have a 8 wire motor, so you have wire a,b,c,d and e,f,g,h. (these can be found in the motor data sheet.)

The driver chip sheet shows the connections for 6 wires.

You need to wire the stepper motor to the chip as follows, stepper motor wires on the left:
a-> Motor D
b&c -> C/T BD
d-> Motor B

e->Motor C
g&f->C/T AC
h-> Motor A

As you can see form above b&c must be connected, as are g&f. The only difference between the 6 wire and 8 wire stepper motors is that in the 6 wire these connections are made inside the stepper motor itself

Dave

yeah, that's exactly how I have it wired up. What I don't know is if I need forcing resistors or what?

Cheers for looking that up by the way, you didn't have to go to that much effort

themole

You shoudln't need any more hardware than that.

Does the motor move at all?

you should be able to test it by building a small circuit yourself

Dave

No, the tech lads told me the motor should heat up or so something at least. I'm feeding the board 5V DC and 1A into the M+VE and everything is fully grounded. I also have the M+VE B/D and M+VE A/C connector soldered together.

themole

Have you hooked up an oscilloscope to the driver output to see if the correct signals are being sent?

With 200 steps per revolution you would have to get it to move a lot of steps for you to notice any movement in the motor itself.

You should be able to test the motor with a bank of switches, you could flip the switches to simulate the driver chip op. This should confirm that the motor is working anyway.

themole

One other thing, the stepper motor is rated at 1amp, but it might need more than that to get it to move in the first place

Dave

I'll try the oscilloscope, i'm worried about fecking up the board though, with too much amps. I'm not an electronic engineer, i'm mechanical so I don't know alot about this stuff.