Parallel Port Question

[IMSlo]

I just bought a new laptop. It is equiped with a 160 GB harddrive and of course Vista. I am toying around with installing Ubuntu and EMC2 as a dual boot system because I think the harddrive is big enough to handle it. I built JRGO's machine a couple years ago. I have always wanted some type of graphical display but can not justify buying software because there is no return and I only run the machine occasionally.

I have two gnawing questions that I must resolve before taking the plunge.

I am running a Hobby CNC 4aup (or what ever number) chopper board and of course it is connected to the computer via parallel port. My new laptop has nothing but usb ports. I saw a usb to parallel port cable where I purchase my computer. It was very overpriced ($50). I was just trying to find out if there was such a thing. I could probably get one much cheaper with a little research.

Now after all that blabber question #1.
Will this usb to parallel port work with EMC and my chopper board?

Question #2
All of my G Gode will be generated by Windows applications.
Will Windows generated G Code work with EMC2?

Thank You.

[samco]

First I would download the live cd from http://www.linuxcnc.org/content/view/21/4/lang,en/
and run the latency test on it.
http://wiki.linuxcnc.org/cgi-bin/emc...I_Latency_test
to even see if your portable will work.. Newer portables, well portables in general, have issues with realtime.

A usb to parrallel conveter will not work..
You might be able to get a pcmcia card (pccard) to parallel converter although I don't know 100% if that would work.

Yes - gcode made in windows will work in linux. (you may have to edit the post to work with the emc2's ngc format. It is similar to fanuc)

[pminmo]

Right now your options is usb and proprietary software, or a parallel port card and windows software like Mach3 or Linux and EMC2 with the parallel port card.

[IMSlo]

Thanks Samco

I guess your reply pretty well killed this idea.

I won't go to a lot of trouble to do this and I'm certainly not going to screw up my shiny new computer trying to do it.

[neilw20]

Welcome to the wonderful world of no backward compatibility!!, driven by the BIG HUNGRY manufacturers. I use win98 and XP junkbox computers. Join em all together with network cables, so you can use the best platform for whatever software/hardware (that still plugs in).
Interrupt latency is a real issue with real time control. More horsepower (=$) usually wins, but do we hit a golf ball with a cricket bat?

[Meduza]

http://www.superlogics.com/parallel/...-961.htm#fdesc

I belive this one would work, tough i have not tried it.

[NC Cams]

There are a couple more potential issues that one can face with a laptop and LPT port.

The laptops tend to use low power 3.3 or so volt LPT's. These can cause problems if the BOB that you're using are looking for higher power, 5volt digital "HIGH's".

The next issue involves real time interfacing to/with the LPT port. The power conservation programs used in some laptops can result in power being interrupted to the LPT port when the uP thinks it is ok to do so.

In any number of prior instances (do a "laptop" search on the site) these and other reasons why laptops should NOT be used for machine control have been cited. You are more than welcome to ignore this suggestion and/or recommendation, at your own peril of course.

[IMSlo]

I appreciate all the replys.

I am now running an old HP 166mhz with 32k ram and Windows 98 that I actually dug out of a dumpster. It has proven to be the most dependable machine that I have.

I guess the laptop thing is over with.

[ger21]

You can run Mach3 under Vista with an ncPod through USB. http://ncpod.oemtech.com/

[cnczoner]

Most (but not all-) USB-to-parallel converters are designed for just printers, so do not connect all the signals. You need a "True EPP" or "True Parallel" converter. Google should find it for you. Verify that it produces proper 5V signals.

On the SW side, FTDI makes a chip that allows electronics tinkerers to use USB ports. Not suggesting that you fiddle with electronics, but they apparently provide a driver that acts as a parallel port on the PC side (so the application "talks parallel") then converts it to USB signals out the USB port, and their specialized chip converts the USB signals to parallel signals (for interfacing to a microcontroller, etc). I know they make a USB-to-serial converter, but perhaps a USB-to-parallel also, and I'd think this would solve your problem. You can contact/ask them here... http://www.ftdichip.com/Products/FT245R.htm

Cheers,
-Neil.

[cnczoner]

BTW, this statement is interesting as it suggests that Ubuntu requires tremendous harddrive space, which is contradictory to my Linux experience. I've always felt that Linux needs much less resources that Windows, though I'm not sure of what's in the Ubuntu distrib. I actually have a bootable linux distrib running on a 64mb flashdrive!

Or were you suggesting that you had enough space for a dual-boot system? If so, I should point out that I'm currently running Suse and Win2k on a 30GB HD currently with lots of space leftover for my data/photos/etc.

Cheers,
-Neil.

Originally Posted by IMSlo I just bought a new laptop. It is equiped with a 160 GB harddrive and of course Vista. I am toying around with installing Ubuntu and EMC2 as a dual boot system because I think the harddrive is big enough to handle it. ...

[samco]

The issue isn't as much usb-> parallel... It is that Emc2 dosn't have a realtime usb driver. Usb doesn't lend itself very well to realtime so none of the developers have wrote one. The ncpod is a motion controller.. The motion gets downloaded to it from mach - and it runs from the ncpod. This would not be a good match for emc also.

Equipment that moves the motion outside of emc isn't a good match. EMC is a closed-loop motion controller, unlike anything else that's affordable by hobbyists. Steppers work because EMC fakes itself out with a made-up position value for the loop control.


The