Hi Guys,

I have decided to build a very small prototype of my CNC Plasma machine before I take the plunge with the finished article. I have experienced with previous projects that building the machine of your dreams without any experience is usually biting off more than I can chew. My plan is to use some parts from old printers and steel to build up a mock unit that will draw the parts onto a sheet of paper. This will give me a much better grounding for when I go try build an 8 X 4 machine. I was hoping to use the parallel port to drive these small stepper motors.

Anyone know of a program that can output through this port?

Thanks

Ronan

Few that I can think of off the top of my head...

Turbocnc http://www.dakeng.com/turbo.html
mach http://www.machsupport.com/artsoft/index/index.htm
EMC2 http://www.linuxcnc.org/ <-my fav

Thanks Samco for your reply.

I have downloaded a version of Mach3 to my pc. Looks like an excellent tool.

In order to build my prototype cnc machine I have stripped down an old printer as my Y axis which has a built in bipolar motor.

I will build the X axis with a unipolar motor i have lying round and most probably a belt and some linear guides like weldtutors. I have an old motor controller board that I was hoping to drive the unipolar motor with. (rs 217-3611)

Datasheet is as follows.

http://www.rs-components.hu/ds/425_6241.PDF

My motor is a http://www.nisiki.net/Catalogues/Motors/NMB/PM55L.htm

I am a bit unsure of how to connect this motor up, partly as I do not want to blow my motherboard to shreds ( I have a breakout board in the post) but I would like to try and get things moving (well really turning).

I am getting signals out from mach3 on ports number 4 and 9 (stripped a spare printer cable)
about 3.6V for direction
and a pulsing for the step (cant actually see it on the multimeter but its slightly lighing up a LED when the X axis in Mach3 is moving)

What signal do I need to supply for the clock signal to the board.

Do I connect the step signal from Mach3 to the Full/Half Step port on the control board.

If anyone can point me in the right direction I'd really appreciate it?

Sorry if this post is in the wrong forum.

Regards,

Ronan

You can't drive a motor directly off the parallel port. First the max drive current for a parallel port is about 15ma (.015 Amp) and it's at 3.3 to 5 VDC. It's made to drive a MOS chip inside a printer. Even some motor drives need more current than that to operate.

All parallel port from software (EMC, MACH3, TurboCNC,) use Step and Dir signals. The Step would be considered the "clock".


You are going to spend a lot of time putting together a table that will in the end be worthless (except for entertainment). Few if any of the parts will be usable in a bigger design and bigger designs with bigger motors will need different gearing, slides and linear motion components. You will end up going a lot of it twice...true you will learn from the mistakes, but if you invest an equal amount of time reading and studying this forum and the hundreds of machines users here have built it will be like going to CNC college.

Tom Caudle
www.CandCNC.com

Tom,
Thanks for your input. Its great to be getting advise from a CNC Guru. I hope to do a deal with you in the future on a plasma set up if you will ship to Ireland?

The main reason I want to build a small prototype is to learn. I am worried about spending 5000Euro on building a machine and making a mess of it. At the moment I cant even drive a stepper motor using Mach3 let alone try and control 3 axes and a tool. Id really like to gain some experience in simply controlling motors to start with. One step at a time and all that (no pun intended)

On the point of the small prototype I already have a Y axis..Straight out of a printer. I reckon I can make the X axis in one day out of scrap steel lying around. The way I learn is by reading something and then manually doing it. Its usually during the manual part that things start to click in my head. The prototype will not be extremely precise. I am just looking to move an x and y axis and try and get it to draw basic shapes to start. I have been reading the forum for about 6 months now and am just starting to get brave enough to try a table for myself. The other point is that I can work on this in my house rather than my cold workshop because it is so small.

With regard to connecting my current setup as discussed previously:

If I connect a 24V power supply to the stepper control board,

Connect the direction signal from the parallel port (Mach3) to the direction signal on the stepper control board

Connect the Step signal from the parallel port(Mach3) to the clock input on the stepper control board

Set the full step/half step input and the preset to 0. So I should be in half step mode .

Do I need to connect the ground of the parallel port to anywhere?

Do the signals from Mach3 need to be amplified in any way?


Thanks again for your help.
Ronan..

For your driver card:

A lot of your questions are specific to the driver card you have. The amount of drive current needed (from a parallel port) is determined by the inputs on the drive card. Some require no buffers, others may not work off the low current lower voltage outputs of recent parallel ports.

Your driver card may have an 'enable' pin that needs a logic signal (high or low?) to let the signals through.

No ground to the motor card = no signal. You have to have a ground return for the logic signals. On some cards/drivers the common is a +5 (supplied externally in most cases) and the step and dir signals are active low, meaning they are the ground return.

Sometimes trying to use poorly documented or poorly supported electronics can end up in a long learning curve that will cause frustration and often stops the project.

Tom Caudle
www.CandCNC.com

You might be interested in a learning kit that is avalible on ebay. Do a search for a store named "Hubbard CNC" Once you find the store look for educational or similar titled sub heading.

I'd highly reccomend you use at minimum a opto isolated break out board for your experiments. It will go a long way toward protecting your parallel port on your computer.

Hi Guys,

Its been a while since I got time to spend on my CNC dream machine. I am still hoping to build a small prototype machine that will draw out shapes with a pencil first, before I plunge into the real machine. I got an hour or two of this test rig started tonight.

I cut two lengths of 42mm pipe that I had lying about.

I cut four pieces of 80mm x 3 box section which will be used to hold the pipe. (similar to weldtutors machine).

I made up two trucks for carrying the gantry

I also stripped down an old printer that I had. There is a bipolar stepper motor in it and I am going to use the printer ink head carraige as a Y-axis. I need to buy a bipolar stepper motor driver for this motor. Is there any way to find out what Voltage and current this motor needs to operate properly. It is an epson EM-293 8X0905A. I have searched Google on this and not found anything useful... Is there any test I can do to find this out. I also have to go and buy a DC power supply so I would like to buy one that will run these motors.I was looking at a triple power supply which outputs 5V and 12V @ 0.5A and 0-30V with adjustable current up to 2.5A Because this is only a test rig I wasn't going to buy top of the range control boards. If anyone could advise me I would be most appreciative.

Regards,
Ronan

Hi,
For the size 17 steppers that you have there all you need is an old PC computer power supply. It has the 12 volts for the motors and 5 volts for the controller supply. (if you need it). The more voltage you have the faster the motors will go but there is a trade off on torque which drops off considerably with speed and 12 volts is ok.
I built a small router a while ago using size 17 steppers and PC power supply to test how good they were and also try out some model plane 3 phase motors and they are surprisingly powerful for their size. I still had to gear them down a bit, about 3:1 , but they perform admirably. It took about 14 days to build with a lot of head scratching. :-)
Here is a link of it on YouTube.
http://youtube.com/watch?v=-cOkD-4wF2I

If you buy a driver then get a microstepping one with 8 or 10 steps per step. Don't go for the full step or half step unless you have a 5 phase drive and motor which give you 500 and 1000 steps per rev respectively. Half and full step on a bipolar motor is very jerky and adds to vibration and noise.
Have fun with the build.
Rich.