connecting

[KrashKing405]

What is the best way to connect to the parallel port? Should I use a connector on each end, or cut the centronix end off of a printer cable?

[widgitmaster]

Not sure I understand your question, but rs-232 cables come with every gender combination of DB-29 plug or socket, not just the centronics type!
All you need to do is find a cable with the ends to match the computer and the other device you have!

There are millions of companies that sell these cables on the internet, just search Google or Ebay for "DB25 Cable"

Eric

[KrashKing405]

I'm trying to use items that I have scrounged, or already have. I have a few printer cables, plus the boards out of the printers I salvaged for the steppers, optical switches, power supplies, etc. I kept the centronics connector off one board, cut out the board around it. I could make an ugly looking breakout board with it.

[NC Cams]

Yes, you could kluge up an iterface by cutting out the connector. For a 1 off, that would surely work.

Or, you could to to ExpressPCB and D/L a free schematic and board layout program. They have a neat "mini-board" service where you lay out anything you want in a given, standarized space (thru hole or SMT, your choice) for about $50 (less than $21 for the 3 pieces allowed. Delivery is 2-3 days.

You could make up a "universal" one and use it in plug and play fashion. Imagine, no more cable cobbling - just mini break out/in boards with one or more cable connectors that go to screw terminals. Real classy, no???

Ex: DB9 x 2 on one edge, DB25 on another, whatever on the third and screw terminals on the 4th. You can jumper connect the DB's to the screw terminal traces to allow for re-use later in another configuration.

Jumper connect as desired, plug, play, done.

Not as cheap as chopped out sections but it could end up being MUCH less of a hassle all things considered.

[KrashKing405]

Like I said, I'm trying to use or resuse item that I already have, as my budget for my entire build is rather small. I'm already collecting some of the electronics parts to build my controllers. My next problem is going to be finding a power supply to run the steppers and the electronics.

[NC Cams]

Go to Bob Campbell's site and download plans to build one. Some stuff you can easily salvage. For transfomers, bridges, caps, misc trinkets, check out Electronic Surplus Inc in Cleveland OH. They have a website and all kinds of stuff to drool over.

You can also daisychain AT and ATX power supplies - these are quite affordable anymore in used computer shows - some computer shops give/throw them away, especially out of old PC's - such a deal. We cruise thru our local recycling shop and get them there for peanuts as well.

[KrashKing405]

Originally Posted by NC Cams Go to Bob Campbell's site and download plans to build one. Some stuff you can easily salvage. For transfomers, bridges, caps, misc trinkets, check out Electronic Surplus Inc in Cleveland OH. They have a website and all kinds of stuff to drool over. You can also daisychain AT and ATX power supplies - these are quite affordable anymore in used computer shows - some computer shops give/throw them away, especially out of old PC's - such a deal. We cruise thru our local recycling shop and get them there for peanuts as well.

Well, the PDF on his page suggests voltage supply of about 20 times the rated voltage of the stepper. The 2 larger steppers I have are rated at 24V, so that'd be 480V. Not 100% sure I want to try and mess with anything that large.

[pminmo]

Originally Posted by KrashKing405 I kept the centronics connector off one board, cut out the board around it. I could make an ugly looking breakout board with it.

You should be able to pick up a db25 to 2b25 printer cable about any junk surplace place for next to nothing. The old Centronics connector wasn't used a lot on parallel printers for PC's.
http://www.mpja.com/productview.asp?product=2887+CB

http://www.allelectronics.com/cgi-bi...ER_CABLE_.html

Originally Posted by KrashKing405 The 2 larger steppers I have are rated at 24V, so that'd be 480V. Not 100% sure I want to try and mess with anything that large.

I suspect that is what the motor torque ccurves were based on with a current limiting driver. Look at the name plate for a current rating and coil resistance.

[NC Cams]

Sadly, using what you have or using what you can get a deal on isn't always the most economical way to source surplus stuff so as to build DIY CNC hardware.

Buying something on a hunch without doing any pre-engineering adds further risk of buying the wrong or useless stuff. But, sadly, you're learning that fast.

Maybe that is why you got what you got, especially if it was inordinately cheap - it was some odd-ball industry stuff that was totally ill-suited to any use but what it was designed for.

Perhaps time to unload it on E-bay and start over... only with some engineered paramters in hand before you do any more shopping.

Live and learn.

[KrashKing405]

Unless I'm reading the datasheets wrong, which is possible, the PM55L-048 says the current/phase under bipolar is 800mA, and the coil resistance/phase is 5.5 Ohm. The PM35S-048 has a current/phase under bipolar of 600mA, and the coil resistance/phase is 6.6 Ohm. As these parts were 100% free, I'd say they were a great deal NC.

[NC Cams]

Per your prior post re; power supply sixe indicated, "...2 larger steppers I have are rated at 24V, so that'd be 480V. Not 100% sure I want to try and mess with anything that large....".

Your words, not mine. My comments about the viability of the buy was based upon this conclusion, no more, no less.

"Larger" as in something the size of a car starter motor (I have some that big) or little/big as in hard core printer motor - can't tell what size "big" is/was in this instance

Yet in post #10, we get a totally different picture via the introduction of much more pertinent specs. Too bad this info wasn't provided at the outset.

Had it been, I'd not have said what I said.....which was merely a caveat to others who might go for a "good deal" on something only to find that it wasn't so good afterall. It's happened before and hopefully we can prevent a recurrence.

You could EASILY daisly chain 2 ATX power supplies together to achieve what you want/need. Or do the Campbell system.

Here's easy to follow, unambiguous data for you to figure out what you need:

Daisychaining ATX power supplies:

http://www.cnczone.com/forums/showth...015#post142015

http://forums.bit-tech.net/showthread.php?t=108208

Linear P/S design/construction
http://www.campbelldesigns.com/files...ply-part-1.pdf

Servo amp P/S design
http://www.elecdesign.com/Articles/A...7635/7635.html

Servo motor , servo amp, powersupply sizing for CNC
http://www.rutex.com/pdf/Mystique2.pdf

Clearly I can't be of proper assistance. I"m obviously misinterpretting things from the data that is perhaps being provided out of order.

[pminmo]

Looking at the specs, it was the drive voltage at 24V, not the motor rating as I suspected. At less than 30ozin, these motors are pretty weak.