Using parallel interface.

It is not a simple USB 2 parallel converter! The USB board has a mikrocontroller that generates the parallel signals itself. AND it is a dongle tightly coupled with the software and vice versa. Neither of both runs without the other.

If you want to run the machine with Mach3 in the end, you have to remove the USB board and replace it with a parallel interface of any kind:
* There are people who build an adapter cable
* The files for milling a parallel-board yourself (for example with WinPC starter) are available in the forum
* ...

The big advantage of a USB board (could also be a USB board designed for Mach3 or UCCNC) is, that the speed of the PC or Laptop is irrelevant. I run my steppi with an old netbook. Timings can be created much more accurate by a mikrocontroller. And in future it might be harder to find a replacement if your laptop breaks.

Hi MagIO2

Thanks for your response - unfortunately that leaves me even more confused as to the interface possibilities. Perhaps some simple block schematics showing typical hardware and software possibilities would clarify the situation for us newbies.

I make this comment after searching the forum for "parallel-board" and found a lot of information from the German forum. Unfortunately I don't have enough knowledge of German to be able to make sense of this information.

In your post of "Parallel 2 SC X1" on 3rd Jan 2015 I see an adaptor from a DB25 connector to an Arduino UNO. I do not understand what role the Arduino plays in the overall system - is this the USB board that has the microcontroller on board which you mention in your reply. This board presumably generates the step and direction signals that the stepper motor drivers require, but is the input USB data generated by the WinPC starter software?

If I do use a laptop or PC with a parallel interface running MACH3, is a simple DB25 / DB25 1 to 1 cable all that is required between PC and Stepcraft system, since MACH3 will generate the correctly timed step and direction signals from the g-code.

I apologise if this seems rather basic information but would appreciate some guidance from you.

Thanks

If you use a parallel interface and MACH3, then MACH3 is generating the signals. This is why you should run MACH3 standalone - no other software, no internet .... . Still there might be drivers for your particular hardware which decrease quality of signals because of too much interrupt handling code which runs unpredictably. There are chances that your machine will not run as smooth as it could up to it won't run at all.

For LinuxCNC there is a compatibility test which tells you wheather your hardware is good enough or not. I can't tell wheather there is a similar tool for MACH3.

I'd even prefere a controller solution if I would use something better than the netbook.

I bought my machine with SC USB board and the WinPC NC starter, as I was totally new to CNC more than a year ago. The maximum you can save is 20€ if you replace the SC USB board by the SC parallel board, but then you have no software at all.
I came along with the starter software for quite a while. But ... it's a pain not everybody will withstand that long, because the Starter at that time did not support automatic multi-pass cutting. So, if you want to cut something deeper than the cutter can handle in one pass, you have to cut once, update the cutting depth, cut again, update the cutting depth ....

A lot of people here in the forum use EstlCAM as a CAM tool, so I also bought this software. After several software versions EstlCAM additionally offered the possibility to directly control the SC with an Arduino UNO R3 board. This replaces the SC USB board and the WinPC NC software. Compared to WinPC NC Starter this is a progress, because EstlCAM creates/handles g-code, which gives you full 2,5D and even 3D cutting.

So, I gave it a try. I used the WinPC NC Starter to create PCBs for
1. an Arduino Shield, which can directly replace the SC USB board - it even fits into the machine
2. a parallel board, which is now fixed in my machine and connects via normal parallel printer cable to a PC or to the parallel 2 SC XC1 adapter
3. the parallel 2 SC XC1, which can be used to plug in either the SC USB module or the Arduino Shield
4. somewhen in future I'd like to build my own controller

Why? Because I like to have the opportunity. I tried EstlCAM and it is really nice for cutting all the 2,5D and 3D stuff I did so far, but it did not work nicely together with the PCB software.

The Arduino UNO R3 is flashed with fimware from EstlCAM. It accepts g-code which is generated by EstlCAM. The EstlCAM solution is also closed source, but it is inexpensive enough.

Of course there are other possibilities. For example grbl controllers (or projects dereived from grbl), which basically do the same thing. ( Just to add another piece of confusion 😆 )

I think this was a nice trip on the road to "learning CNC", which did not cost too much money compared to the WinPC NC full version. 200€ versus 35€ + some material for the PCBs. And the doors are now wide open.

Hi MagIO2,

Thank you so much for that - it is most informative. I think the light has dawned at last!! It seems you have been down a similar upgrade path that which I thought might be appropriate for a beginner.

I am aware of the timing pitfalls of using MACH3 in a Windows machine environment, and using the Arduino to handle the g-code is a neat move as clearly the code can be generatedby a wide variety of CAM software if so desired.

I have had a quick look at EstiCAM just now, and it looks very promising at a very attractive price too. Looks as though your learning/upgrade path is the one to follow for me as well.

Thanks again.

Regards.

Hi,
...
Once I have some familiarity with the machine I want to use MACH3 on a laptop with a parallel port and running Windows XP. Does this mean that I have to remove the converter board if it is a separate item, or does the Stepcraft accept either USB or parallel data as delivered in the starter kit.

I would skip the starter option and get the machine with parallel port if your plan is Mach3 and XP anyway. Mach3 is free to use in demo mode and 500 g-code limit should help you get familiar with the machine before buying the full version. Laptop probably needs some fine tuning unless you use an external controller like UC100.

Hi Tikka,

Thanks for that thought, but as I am quite new to CNC it would seem prudent to make haste slowly and learn to walk first. The suggestion of the UC100 is an interesting one as a fallback if my tweaking of the laptop fails to give required accuracy of the step timing.

The MACH3 software apparently comes with a test tool to check the scatter of timing pulses, and as the laptop will only be used for CNC I will be able to shut down most of the extraneous processes that XP runs by default (I hope).

Regards