Parallel to USB....

[dbtoutfit]

So like an idiot I snagged a Parallel to usb adapter cable so i could use my new cnc on my brand new laptop. One thing I forgot... ummm will any controller software read through usb? and futher more this can prob get even more complicated.

So heres the Q.. Anyone done this and/or anyone know any info on trying to do this.

Another thing I was thinking of running my machine off this old school lappy like a P133, Anyone know a Windows based apps like Mach that will run on this system?

Also I have read ppl saying you dont need to use an older pc due to pulse rate etc but as a certified computer tech I do not see where this is an issue. At 133mhz you can run alot of info and the parallel port will only do the same on new machines as it has with the older machines for years (other than a few very small advancements)

Anyone can shine some light on this as well?

LOL I cant keep my machine like it is, as i have it in my office and its taking up alot of room plus I have had to move my pc around etc..

Anyways any response would be great.

Thanks

[Karl_T]

I have no personal experience, but I've read on CNCZone that the USB adaptor won't work on Mach but a PCCIMA (sp?) adaptor will.

If you scrounge just a bit, you should find a suitable old computer for $50 to $100. Ebay runs a little high on these, but there's plenty available.

Karl

[dbtoutfit]

hi, yea the PC cards are 98-150$ which is insane for what it is.
I'm looking at another lappy

[ljogwin]

I am using a USB to Parallel cable. The parallel end has the electronics in it.
Make sure you get one that is bi directional. In other words, make sure it is EPP or it will not work. I feel better using it instead of the internal port of a Laptop cuz, I would rather replace the cable than a laptop motherboard.

LJ

[ShayArnett]

The reason slower pcs limit your pulse rate isn't the parallel port as far as i know, its the fact that it can't process the g-code fast enough to generate the pulses to send.

[dbtoutfit]

My cnc controller is parallel, I have a cable to take it from parallel to usb. It is bi directional though my system has no loop or return. I am using Mach but I cant seem to get it to make it work.

[dbtoutfit]

Originally Posted by ShayArnett The reason slower pcs limit your pulse rate isn't the parallel port as far as i know, its the fact that it can't process the g-code fast enough to generate the pulses to send.

If just running a gcode you can run it on speeds as low as a 286 cpu.
the last models were mostly 20mghz thats still 20,000,000 comands a second it can process. So I cant see the idea of it not being able to run gcode real time with no delay.

The only reason I see why you could not run on an older machine is if you are running something like Mach as their requirements need a newer machine due to all the processing like converting a jpg,bmp to gcode and the CADing.

I mean.. just saying, I dont want to sound cocky as i mean to simply discuss.

[abasir]

Regular USB-to-parallel adapter WILL NOT work. It's meant for printer only. Printer control is very simple (compared to CNC) and that interface is build into Windows XP.

For Mach 3 to work, you need to see "Parallel Port" under the Ports section in Device Manager. Mach 3 interface direct to parallel port address using it's own device driver.

As for slow computer, bear a few things in mind.
1. Even if the PC is 20MHz, most Intel CPU takes more than 3-4 clock cycle for each instructions thus 20MHz does not always mean 20MIPS.
2. Mach 3 uses it's own device driver clocking the parallel port at 25kHz. That takes CPU resources.
3. Mach 3 interpret G-Code in real time, converting them to movement vectors. Add to that, acceleration and decceleration, constant contouring, etc. You just don't run G-Code... you read, interpret, convert to motion vector, send the step/dir signal to the stepper drivers, etc. All those process are done using floating point numbers which take a lot of processing power as well.

If $100 is too much for PCMCIA-parallel port card, better get a used notebook/pc from eBay.

[Zumba]

There's no way I would use my nice laptop in a machine tool environment.

I can build a nice desktop for about $300. Dell sometimes sells complete systems with monitor for $199.99.

[unterhaus]

Originally Posted by ShayArnett The reason slower pcs limit your pulse rate isn't the parallel port as far as i know, its the fact that it can't process the g-code fast enough to generate the pulses to send.

No, feeding the parallel ports accurate data is pretty hard, and the motherboard manufacturers don't really see any reason to make it faster. For one thing, there are very few new parallel printers.

[Stevie]

good luck running Mach3 on a 286; LOL

needs XP for a start; Art says a 1 gig speed for real proformance

If you want to run a 286; run Turbocnc; but I run it on a P1 200Mhz min

[Elnino]

Generally a USB to paralell port adaptor is not capable of doing this sort of thing. The main reason is that the drivers (and often the chips themselves) will not allow raw control of the signal lines in the port. This means that software like mach3 etc can not send the appropriate step/direction pulses to the controllers.

They are a 'Printer' port, not a paralell port.

I believe there is 1 product on the market made by Belkin (and then it's limited to specific versions) that even has the capability to control signal lines. Then it still needs a specific custom driver to be able to perform these funtions. I belive the people that got it to work were using MacOS too...

I went through all this when looking at running a character LCD off of a USB -> Paralell adaptor.