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usb to parallel
« on: March 02, 2008, 01:13:59 PM »
I am trying to run my max nc cl system from a laptop through the usb.
Am I confused?
Can it be done?

Offline Chip

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Re: usb to parallel
« Reply #1 on: March 02, 2008, 03:04:21 PM »
Hi, Spanky

As far as I now, A usb to parallel adapter cable Won't Work.

There are several usb type control's for Mach3, Thy all have there own CPU to store and send commands from Mach to your step & dir boards.

NC-Pod and SmouthStepper are 2, That I now of.

Hope this Helps, Chip

Offline jimpinder

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Re: usb to parallel
« Reply #2 on: March 02, 2008, 03:10:39 PM »
You are not giving us much of a clue.

What machine - lathe, mill etc have you got, what drivers and more important - what laptop.

When this project first started, the output to the machine was via the parallel port - LPT1, principally because this port was faster, and could keep up with the fast response needed for a CNC system. The system could support a serial port for some of the slower responses.

I run my system from a laptop - but I am lucky - my Toshiba laptop has a parallel printer port - and runs from a 5 volt system. A lot of modern laptops have no LPT1 and only a 3.5 volt system.

What output have you got from the USB - is it USB2 - how does it fan out. To drive the various stepper motors and switches you need about 16 outputs and maybe 8 inputs - so you need a 24 port card, that is as fast as the old LPT1.
Not me driving the engine - I'm better looking.
Re: usb to parallel
« Reply #3 on: March 02, 2008, 06:26:03 PM »
looks like it's back to school for me.
IBM Lenovo Z61m
It sounds like the usb is out but how about the printer port on a docking station, providing that the 5 volts is there?
I would need to buy the second dock.
I am trying to run a MaxNC closed loop system.
I design in solid works and hope to do some prototyping on a home built machine.
I am a designer and have done some work with VB and Galil.

Offline Garyv

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Re: usb to parallel
« Reply #4 on: March 02, 2008, 07:16:57 PM »
Do_you_have_a_PCMCIA_port?
If_so_there_are_a_few_adapters_out_there_for_a_LPT1_output_at_5_volts_Just_be_sure_that_
the_PCMCIA_card_will_fit_the_only_PCMCIA_to_LPT1_Ports_that_I_have_found_
are_the_regular_PCMCIA_not_the_PCMCIA-EXPRESS_ports..
Re: usb to parallel
« Reply #5 on: March 02, 2008, 09:11:16 PM »
I have just ordered a pcmcia adaptor.
lets hope it works.
thank you :) :) :)

Offline stirling

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Re: usb to parallel
« Reply #6 on: March 03, 2008, 06:57:41 AM »
Hi Spanky
Chip's already said this but just to expand a little. Mach uses a drive protocol called "step and direction". i.e. to move a motor it needs to set a direction signal and send a step signal AT THE SAME TIME. So, to drive three motors for example it needs to issue SIX signals AT THE SAME TIME. It therefore uses the parallel port because without external hardware that is the only way that the many control signals can occur in PARALLEL. It has nothing to do with the SPEED of parallel ports v the SPEEED of serial ports. If you want to use Mach with USB which of course stands for Universal SERIAL Bus then you can only send signals SERIALLY. These SERIAL signals must then be collected up by external hardware into the groups that WOULD have been sent in PARALLEL. Once collected up by storing them until you have all signals required for ONE 'pulse slot' the external hardware will then issue these signals in PARALLEL to the motor drives. The only SPEED issue is that if you use a USB and the associated and required external hardware then the USB must be able to send data fast enough that the SERIAL data can be parallelized in the same time as a parallel port could have sent it.
Hope this helps
Ian
Re: usb to parallel
« Reply #7 on: March 03, 2008, 11:18:45 AM »
Thank you for the extended version.
It makes perfect sense when you think about it.

I am hopefull that the PMCCIA adaptor will do the job.

BTW, my real name is Jim Weatherly, Spanky is my cat.
My home page is  www.weatherlycustom designs.com

Offline jimpinder

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Re: usb to parallel
« Reply #8 on: March 03, 2008, 01:04:49 PM »
Why use the name of your cat???

From one Jim to another - yes Stirling has the nub of it - you can use a serial connection if it can send the information fast enough - and in this case we are talking about 16 times or more faster that the parrallel port.

I got a pcmcia adaptor the other day for my laptop to try and get a USB 2 output to run a camera - it failed miserably. I hope you have more luck - I take it it is a PPMCIA to parrallel port card. It could work - best of luck.
Not me driving the engine - I'm better looking.
Re: usb to parallel
« Reply #9 on: March 03, 2008, 11:44:52 PM »
A rose by any other name doth smell as sweet.
What's in a name?