Need some help on the eletronic side of things

Hi, I'm new to this stuff and I need some help on the electronic side of things. I was to design a small/medium CNC router using some HobbyCNC 205 or 305oz stepper motors. I would like to use open source component as much as possible and I'm planning on using EMC2.

I've been looking on http://www.pminmo.com but I'm not sure what exactly I would need for such a system... so if I understand correctly I need an interface board and then stepper drivers for each stepper motor and a power supply.

What I'm really not sure how it works is how all those components connect together... I was looking at the 4 axis opto isolated interface but how does it connect to the stepper drivers? Where do all those x1-*, x3-*, etc connections go to?

Anybody got some good links or info on how all this connects together? I know I could just buy the HobbyCNC controller and be done with it but I prefer to do it myself and learn some new things along the way.

Any help would be appreciated!

TIA!

The basic idea is that your cnc program will provide a step and a direction signal for each motor (5vdc). That means that you will run a pair of wires from your parallel port to each drive. The drive will provide 4 high power output wires to be connected to each motor (3 if a servo). The drive is powered from a seperate power supply.

A single parallel port has 12 outputs, pins # 1,2,3,4,5,6,7,8,9,14,16,17
A single parallel port has 5 inputs, pins # 10,11,12,13,15
Pins 18 thru 25 are ground.
You may want to have overtravel switches mounted and wire them to the drives or as an input to your cnc software. Home switches, e-stop as well as enable signals may be considered as crucial options.

Hope this helps.

Quote:

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Originally Posted by bluejay_ca

The basic idea is that your cnc program will provide a step and a direction signal for each motor (5vdc). That means that you will run a pair of wires from your parallel port to each drive. The drive will provide 4 high power output wires to be connected to each motor (3 if a servo). The drive is powered from a seperate power supply.

A single parallel port has 12 outputs, pins # 1,2,3,4,5,6,7,8,9,14,16,17
A single parallel port has 5 inputs, pins # 10,11,12,13,15
Pins 18 thru 25 are ground.
You may want to have overtravel switches mounted and wire them to the drives or as an input to your cnc software. Home switches, e-stop as well as enable signals may be considered as crucial options.

Hope this helps.

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Thanks but I understand that the program uses 2 pins to send the step and direction to the driver and that the driver uses that to control the motor, what I'm having problems with is what's happening between the parallel port and the stepper motors, like where is the higher voltage entering the system to power the motors and stuff like that.

Quote:

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Originally Posted by Forbidden

Thanks but I understand that the program uses 2 pins to send the step and direction to the driver and that the driver uses that to control the motor, what I'm having problems with is what's happening between the parallel port and the stepper motors, like where is the higher voltage entering the system to power the motors and stuff like that.

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2 pins from the parallel port go to the drive, to deliver the step and direction signals. The motor power supply connects directly to the drives. Some drives need an additional 5V suplly to power them, some get their power from the motors power supply. The motor power supply connects directly to the drives.

So, from the parallel port to the stepper motor, you just have the 2 pins per axis, which go to the stepper drive.

I an a total electrical newbie and fried my previous driver boards because the electronic hook up is so complicated, and the use of encripted three letter codes to describe the connections was way beyond me. Especially when thoes codes change from board to description.

My 4 year frustration with electroniocs and the connection of same was SOLVED by Probotix http://www.probotix.com/power_supplies.

They have WONDERFUL color diagrams showing the entire wiring diagram and how each one connects, Power supply, Breakout board, fuses, drivers, and steppers. If you only looked at the colored pictures you could wire it completely and safetly.

I baught their Probostep Uni-Polar Driver, which has built in protection against motor coil Opens or Shorts. (An open fried my previous boards) You will need to use Uni-Polar steppers not Binary with this driver though. I already had steppers so I didn't need that from them.

Also baught their PBX-RX RF Isolated breakout board. This isolates your CNC power and signals from going back into the PC and possibly frying it. ( It would be my luck to fry it)

They have piece parts or full kits. and Hey THEY WORK!!!

Hager

Quote:

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Originally Posted by Forbidden

Thanks but I understand that the program uses 2 pins to send the step and direction to the driver and that the driver uses that to control the motor, what I'm having problems with is what's happening between the parallel port and the stepper motors, like where is the higher voltage entering the system to power the motors and stuff like that.

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Forbidden,

This (PDF below) might help. It's from the manual for the MicroStep driver board from EAS here:

http://www.embeddedtronics.com/

Check out the site. There's a menu on the left of the page that will get you to the MicroStep stuff. I've built 3 of their boards and they're great. They sell only the bare boards, so it's totally diy, but the plans are pretty easy to follow.

- Don

The stuff on Phil's site is a good place to start, he has a lot of info aimed at the beginner CNC side of things, he also contributes a lot to the open source side of things.

He usually has boards for the drivers on his site to make things easier.

Russell.