@Bijil_Baji
You cannot use a USB to parallel converter for CNC, but don’t let me telling you stop you from trying. I suppose if the CNC machine has an on board computer you could transfer the nc file over USB to it. That is basically how GRBL works, but it’s crap.
Aparently my lengthy answer vanished.
Yes, a USB 2 parallel converter doesn’t work.
To use a parallel port you should use LinuxCNC as it features a realtime kernel.
Beware that it’s quite old and they are struggling to get it updated to recent packages and a recent kernel (or so I’ve heard).
Parallel port are limited to only a few inputs.
Also make sure your LPT breakout cards has opto-isolated inputs and galvanic isolation to provide power for these inputs.
It will often not have a PWM output to control your spindle RPM. Check that before buying one.
The USB-cards I use are specific for the control software I use and have a command buffer for the next multiple seconds. They are no parallel ports at all. They execute commands and generate a timing for stepper motors in dedicated hardware. They have a ton of inputs and outputs as they are not limited to the few pins of an lpt port. You are however limited to that one, commercial control software running only on Windows.
The free EMC software is generally considered a more advanced software then the commercial MACH3 I use.
@Marcus_Wolschon
You can build your own kernel to use with LinuxCNC. RTAI builds against quite recent kernel versions. I don’t much care for LinuxCNC’s disk image anyways.
@Paul_Frederick @Marcus_Wolschon is this a good board this is a USB based board
I hope i not bothering you guys but i am a newby and you guys are pros in this field. having guide is better than going blind.
@Bijil_Baji I use that board in my small CNC but I payed much less for it.
I don’t know if it’s possible to use it with EMC2.
@Marcus_Wolschon
LinuxCNC formerly known as EMC2 does not support real time USB output. The USB protocol itself does not support real time either for that matter.
@Paul_Frederick what are you talking about?
This board DOESN’T NEED anything to be real time. That’t the whole point of it.
It’s not a breakout board. It gets commands and does all the realtime stepper pulse generation in itself.
Also YES, USB does support isochronous data transfer.
@Paul_Frederick @Marcus_Wolschon this might be a stupid question i have used reparap 3d printers that use RAMPS and Arduino MEGA which runs with gcode shouldnt it be affected with the same problem. To that of my knoledge both of them are in a way same converting gcode to pulses to move the stepper motor. the main problem with arduino is that it can only handle one instruction at a time. but wouldnt it work for them??
@Bijil_Baji They dont have that problem because the Arduino is generating the stepper pulses and not the PC.
The PC is only making sure that a queue of commands in the RAMPS doen’t run empty. It doesn’t matter if it sends a command 10ms early or 1ms later.
@Marcus_Wolschon then wouldnt arduino based design be a better choice for them rather than parallel port based design??
@Bijil_Baji Some people have indeed build such a thing using a Beaglebone Black.
@Marcus_Wolschon any way i will have to start with a Parallel port based design and i have about 4 or 5 arduinos and a raspberry pi lying arround will experiment with them later on.
I made my own break out board. Plans are here:
Checkout Probotix.com and their driver/breakout board solutions. They are also working on a beaglebone black breakout board that ribs of LinuxCNC and works pretty great but isn’t released yet.