Parallel Port 3 Axis CNC Driver, Opto-Isolated, Unipolar Steppers

Step 8 Motors and Power Supply

I am not going to cover motors here there is plenty of great info around on the net and here on Instructables.

Below(the image with blue background) is the the setup for the motors that are included in my Full CNC Kit with Motors, Power Resistors, Wire

All Axis' are have the same pinout, if a motor works on one it will function the same on the others.
A full step means 2 coils are on at once.

Example each bit represents Header 1 - 2 - 3 - 4
1100 - 0110 - 0011 - 1001

This driver does not have any on board resistors or chopping circuitry to regulate current for the motors.

I prefer to place high wattage resistors in line with each motor's V+. Hopefully you can find the datasheet for your motors and find out the required current and voltage for the motor. Then by using a web resistor calculator, you can find the correct ohm and wattage values for your motor.

Each motor needs its own resistor, otherwise it will force multiple motors to share current when multiple are on at the same time.

A 24 volt stepper motor will end up drawing a lot of wattage, be sure you have properly rated resistors to avoid damage.

Some Good Links on Current Limiting:
http://pheattarchive.emporia.edu/projects/stepper/unipolar.pdf

http://www.cs.uiowa.edu/~jones/step/current.html

I have tested this driver with 5 different unipolar motors, they all worked great.


To calculate power supply requirements: Motor Voltage/Motor Coil Resistance = amperage per coil. When full stepping each motor will have 2 coils/phases on at a time so minimum requirement is 6 * amp per coil. Then always use a power supply rated for %150 - %200 higher than the minimum. Switched mode PSUs will work, but will perform extremely bad compared to a capable linear power supply. Linear power supply's can be identified by a large transformer and capacitor probably along with some circuitry, they are more expensive but worth it if you want a nice machine.

Comments

[buddace]

How connect six wires step motor in this board ? sorry is not clear :D

[lilschwoegl]

I still dont understand how the step motors are wired to the connectors.. any help? thanks!

[buddace]

OPs..solved ...I don't see schematic
Another question can I use 16f876 ?? hardware are same only memory source are most ;)

[ChromationSystems]

 Yes you could, they are both pin-compatible. But you would have to purchase the source and change a few include lines and recompile.

[CNCbuilder1]

hi, I have these motors.
http://cgi.ebay.co.uk/4x-NEMA-23-Stepper-Motor-MY103H702-1-8deg-0-98Nm-NEW_W0QQitemZ170460816314QQcmdZViewItemQQptZUK_BOI_Electrical_Components_Supplies_ET?hash=item27b041a3ba
Is this board suitable?
also besides your kit, what else do I need to hook these up? i.e power upply rating, resistors?
Also any chance of adding bit more on resisitors and how ot hook these up,

Thanks

[the merog]

Does the Dot Matrix Printer Motors work?

[ChromationSystems]

They might, Unipolar stepper motors are what your looking for, it should have 6 - 8 wires. Search google for more information on how to identify them