Sebastians Journey with the nanoMoCo & Graffik

So I finally bought a stepper motor to test the nanoMoCo board and Graffik.

http://www.conrad.at/ce/de/product/198398/Emis-Schrittmotor-E547-52500-12-VDC-Halte-Moment-025-Nm-Phasen-Strom-max-06-A-Wellen-5-mm (sorry - German).

Its a 6 lead stepper motor that can be used both in unipolar and bipolar setups.

I soldered the coil ends to the custom connector provided in the breakout board package as described in the documentation and plugged everything together.

First the USB-To-RS485 adapter which calls itself "Dynamic Perception RS485" can't find a device driver in Win7 when plugged in. I managed to work around that by downloading a driver package from http://www.usconverters.com/index.php?main_page=page&id=15 for the FTDI FT232BL chipset and manually installing the drivers through the windows device manager. The port is then recognized as "USB Serial Converter" and showed up in the available list of Buses when starting Graffik under COM7.

I connected a universal 12V power supply to the nanoMoCo breakout board with center pin as +V and barrel as GND. This voltage matches the specifications of the stepper motor. The final version of the nanoMoCo breakoutboard will be able to work with motors requiring 7-24V.

Graffik recognizes the Bus and finds one device connected to it on address3 with name OMAXISVX - I called it "Stepper".

Next I 'll need to tune my stepper driver, by adjusting the current output for it. Going into the scripting section of Graffik, and type:

Stepper sleep disable

Now, the stepper should make a slight noise and start to get warm. (We're enabling the driver.) You should also see the far right green LED on the RJ-45 ports light up. Adjust the small potentiometer marked CADJ on the nM board. Be careful not to try and turn it past the stops in the potentiometer.

If the motor doesn't get warm, and doesn't make any noise as you sweep through the potentiometer, it means the wiring is incorrect. Ensure that 1A and 1B are either orange/blue or red/yellow and likewise for 2A and 2B. Luckily my wiring is correct.

You can adjust the stepper in a couple of ways: you can measure the current being consumed (watching the read-out on a bench top supply), you can read the voltage off of the CADJ pot and do some math, or Chrises favorite way is to just listen to the motor. =) Hear it as it sweeps past the first rise in pitch, and then goes silent. Keep adjusting to a second rise in pitch, and when you hear that, go back to the first and move to the point between the two where the motor first goes silent (between the first and second rise in pitch). In most cases, that is where you want to be.

But, a bench top supply is the best - just adjust the potentiometer until you've set the specified amount of current as indicated in the motor data sheet.

After you're done with that, you can do

Stepper sleep enable

to turn the drive back off.

Now, to make some moves in scripting:

Stepper motor enable Stepper max speed Stepper move

Where is the maximum steps per second you can go (start with around 1,000 and adjust from there)

is a direction to move: one of 0, 1, true, or false. And is something like 200 or so. Your stepper should move now. If not, give it a long move (say 10,000 steps) and adjust the CADJ potentiometer during the move until it starts to move properly.

If you've verified the stepper is hooked up correctly and is able to move, back in the film window, make sure you click on the name of the axis below the dial, it should be highlighted in blue. Right now, it does not auto-select an axis because of some order of operations difficulties. (The part which handles selections receives the signal about a device being there before the model which holds the device, and acts when a selection is received, does.)

The motor moves!