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View Full Version : To usb,or not to usb,that is the question.



Jumbo
17-10-2011, 10:22 AM
Hi all,building my first router,nearly finished the mechanics and on the verge of buying the electronics.I like the look of cambam for the cad etc,as this is my first machine should i go with a usb board.I kind of like the idea if this means i can design on my laptop(in the warm)then take laptop to cold workshop.Im new to this so any suggestions would be great.:smile:

m_c
17-10-2011, 03:49 PM
Personally I'd say USB, as parallel ports are gradually becoming rarer, and can be quite tempremental to setup.

I run a Smoothstepper, and would recommend it, however development does seem to be very sporadic. I stopped paying much attention to the Warp9 forums, but I do know Greg was looking to develop a network based Smoothstepper once he'd ironed out the remaining bugs in the existing SS.
There are other options, such as thr Dynomotion Kflop, but it all depends on how much money you're willing to spend, and what functionality you need.


Regardless of whether you go USB or not, I would suggest that you have a seperate computer for machine control, with just the essential software installed to minimise any issues you may have due to random bits of software causing problems.

Jumbo
17-10-2011, 04:01 PM
Thanks,will go with two computers.What do you think of this http://www.zappautomation.co.uk/product_info.php?cPath=15&products_id=197 I think i only need basic functionality for now,trying to keep to budget is tricky.

Jonathan
17-10-2011, 04:14 PM
What do you think of this [URL]http://www.zappautomation.co.uk/product_info.php?cPath=15&products_id=197[/URL

That or, if you fancy some soldering:
http://www.planet-cnc.com/

I would try parallel first and see how you get on. It doesn't have to cost you anything to try it and see.

I would quite like a smoothstepper, but I'm happy with how the machine runs as it is so I can wait.

m_c
17-10-2011, 04:18 PM
I just seen the replies in your intro thread, about the planet-cnc boards (zapp are selling the ready made planet-cnc stuff)
I've seen them mentioned, but can't think of seeing any build threads where they've been used. I'd suggest having a search over on cnczone, to see who's used them, and what they think of them.


The two major DIY CNC machine control packages are Mach and EMC (linux based and free, but only has parallel port support), and the support for both is high, in both community support and additional features, with Mach pretty much being the most popular.
I'd personally be hesitant to venture from Mach, because it has a lot of expansion potential, an excellent support base, and is very flexible, but it is extra cost (unless you can manage to stay within the demo limits - no run from here, and limited to 500 lines of code are the two main limits).


However, as Jonathan says, the parallel port is cheaper. You just need an older computer, and if the PP and Mach doesn't work out for you, then you can quite easily add a SS with minimal effort.

Jumbo
17-10-2011, 04:40 PM
Thanks for the advice Guys.Im going to start with parallel/mach,(dont want to try to run before i can walk).Can i design in software such as cambam,generate gcode,put code onto a memory stick then transfer to the machine computer with mach installed(Sorry if this a silly question but i am new to this)

m_c
17-10-2011, 04:44 PM
Can i design in software such as cambam,generate gcode,put code onto a memory stick then transfer to the machine computer with mach installed(Sorry if this a silly question but i am new to this)

In a nutshell, yes.

Jonathan
17-10-2011, 04:45 PM
Can i design in software such as cambam,generate gcode,put code onto a memory stick then transfer to the machine computer with mach installed

Yep, that's what I do.
You could use network to transfer the files, but that's just something else that could potentially slow down / generally annoy Mach 3. The computer needn't be anything special. I'm currently using a single core 3Ghz P4 with 1Gb (might be 2) RAM which is plenty.

Jumbo
17-10-2011, 04:59 PM
This looks perfect for me http://www.zappautomation.co.uk/product_info.php?products_id=365 ,do you think there is any other electronic essentials i might need.

JAZZCNC
17-10-2011, 06:01 PM
Thanks for the advice Guys.Im going to start with parallel/mach,(dont want to try to run before i can walk).Can i design in software such as cambam,generate gcode,put code onto a memory stick then transfer to the machine computer with mach installed(Sorry if this a silly question but i am new to this)

Like the others have said it will work direct from the stick but if you plan to run really long code or do lots of 3D which usually creates large G-code files then best or safer if you save to the HD first then run.!
Reason for this is Mach buffers code then reads some more and so on, for most cutting jobs mach's buffer pritty much handles the whole code no problem. But on 3D work or large or intricate V carve and litho pain jobs etc the code can run into multiple thousands of lines. . . . Over a million lines is not Uncommon.! Then mach will periodicly read from the stick and given some jobs can easily be 12-18hrs and often run into days then it's not unknown for the memory sticks to react slow causeing Mach trouble and cause lockup's so it's safer to save to HD then load the code.

Edit:
RE . .Usb or Not. . . .Usb is good but costly, I use the smooth stepper and I'm very happy with it but parallel port is good and cheap.
The problem with PP, well actually it's not a problem persay, it's just thats it's there's such difference between PC mother boards that it's very easy to get a slow PP, It's very common on newer machines that the PP only outputs 3.5V and this can cause trouble with some BOB's and drives.!!
Usb takes this potential problem away, another very nice feature of USB pulse generators is because of they way they work and handle the pulse generation side they take the workload away from Mach so this means they can be used with low spec machines, even low spec laptops, I've known Smooth steppers used on Old pentium 100's.!!

Jonathan
17-10-2011, 08:16 PM
Without knowing the size (?) and application of your machine it is difficult to judge, but for most those steppers and drivers are a good choice. You can run those motors on 70V with the PM752 drivers to get better speed and acceleration, but if that is useful or not depends on the size of the machine. You will also need 4-core CY cable, 1.5mm^2 to go from the drivers to stepper motors and connectors for the motors, though those aren't critical. I have about 100m of cable, so let me know if you need any.

Emergency stop switch
Limit switches


Like the others have said it will work direct from the stick but if you plan to run really long code or do lots of 3D which usually creates large G-code files then best or safer if you save to the HD first then run.!

Another thing is it's not hard to accidently knock the stick/cable out whilst it's running :whistling:

Swarfing
17-10-2011, 09:21 PM
Don't be afraid to give EMC2 a try, it does a lot more than you think not just a free do nothing application. As for interfacing there also the MODIO or MODbus route (still costly).