Hybrid View
-
24-10-2015 #1
I run LinuxCNC and it's fine for most use. I haven't found too many limitations with it. I recently had to change the motherboard in my PC as the old one blew up (I suspect that letting the CPU heatsink fill with dust once too many times did for it!) and as many have found, cheap motherboards do not have parallel ports any more. I bought a cheap PP PCI adaptor from Novatech and that has been working fine with LCNC, in conjunction with a cheap BOB. However, my current router is not too demanding in terms of pulse rate. I'm using a low-end AMD CPU and the latest LCNC download. There's plenty of info available for doing things like changing the PP address so that LCNC can find it when you are not using a standard motherboard port; this is the kind of thing that Windows usually manages for you.
What are the limitations? Some of the free CAM software generates G2/G3 arc instructions, and LCNC is incredibly fussy about these. It wants the start/finish points to be correct to some large number of decimal places and bitches if not. I spent a lot of time in the early stages tweaking gcode by hand to fix this. However, since I switched to using Vectric VCarve for most of my CAM, I haven't seen this as an issue. Bigger problem is that LCNC really doesn't support twin leadscrew designs in that it can't handle homing/squaring properly. This has been an ongoing issue in the LCNC community for years. My new router will be twin ballscrew, so this is a problem. It is also very limited when it comes to external motion controllers (really, I think it just supports/is supported by the Mesa cards). There are apparently very good, but that's the only option. I'm going to be moving to Mach3/Mach4 (haven't yet decided) and CSMIO/IP-M motion controller, hence I shall also have to move to Windows. There are plenty of people who will tell you that the LCNC control screens are an old-fashioned heap of junk, but I use the standard screen setup that comes out of the box and it works.
My first router was a bit of an experiment, cheaply built, to see how I got on. I used LCNC to keep cost down, and never regretted it. I don't see why it shouldn't do a perfectly adequate job with the cheap Chinese routers and I wouldn't hesitate to use it in that situation.Last edited by Neale; 24-10-2015 at 05:00 PM.
-
I also run Linuxcnc and find it very good I have just used the pp for my mill and lathe but I have just bought a mesa card mainly for all the extra input/outputs including encoder for the lathe spindle speed etc. I also find the standard screen set OK there is a new one out though called Gmoccapy and it seems very good.
..Clive
The more you know, The better you know, How little you know
-
25-10-2015 #3
Thanks again everyone for the advice. Greatly appreciated.
At the moment I'm not 100% sure on which software route to go down. I'd probably shy aware from Linux at the moment as I have no experience with it. As CNC is new itself for me, I'd rather begin with an OS I know well.
The Planet CNC seems tempting to me currently as it looks like it could be a bit more beginner friendly.. what did you find was too basic about it?
The only thing is as mentioned, I'm not keen on not being to use other software with the board.. but maybe it's a price worth paying..
OK.. so if I go the planetCNC ethernet controller route.. what shall I do about the PC situation? Shall I build one using the Asus H61M-Pro I have coming or is the energy saving features going to make it completely unreliable? Or as I need a good PC there anyway, shall I just give it a go and if not then buy a cheap pentium 4 or something without the new features..? What would you do if you were me?
-
25-10-2015 #4
-
25-10-2015 #5
Does planet cnc do ethernet? Havent seen it on his website.
https://emvioeng.com
Machine tools and 3D printing supplies. Expanding constantly.
-
25-10-2015 #6
MK3 does USB and Ethernet and is shown on the website under hardware
-
25-10-2015 #7
-
25-10-2015 #8
The problem with PC and PP is that every so often, the cpu goes off and does its own thing for a few milliseconds or so. That's fatal if you are generating a real-time pulse stream. However, if you are using an external motion controller, the PC sends a few seconds' worth of instructions which are then buffered in the external board. It doesn't matter if the PC pauses for a short while as it can catch up later while the motion controller is taking data from its own buffer. Cheap PC or even laptop (notorious for random pauses) should be fine. Buy or build PC - it's up to you.
Last edited by Neale; 25-10-2015 at 12:11 PM.
-
-
25-10-2015 #10
I stand corrected - I was thinking more of the "What do I do about a PC if I'm using Planet CNC or similar external motion controller?" question.
Whether or not LinuxCNC is truly a real-time operating system is one of those religious debates that go on endlessly. I'm happy to agree that, up to some reasonable pulse rate (and that rate is certainly sufficient for many machines) it works fine. I've been using it for more than three years with no observed problems. There are some random timing issues, which is why the LinuxCNC kit includes a latency tester which, in effect, measures how reliably the operating system can respond in "real-time" on some particular configuration of hardware but the answer is often hardware-dependent and there are some motherboards which just do not perform well. It's not related to raw CPU performance but even LCNC can't cope with some hardware. If you want to say that LCNC is truly real-time but is let down by the hardware, I can go with that
Thread Information
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
Similar Threads
-
USB TO Parallel Port DIY Interface
By Lee Roberts in forum Electronic Project BuildingReplies: 42Last Post: 17-02-2018, 07:46 PM -
What is the function of a parallel port breakout board?
By hbx in forum Machine Control SoftwareReplies: 13Last Post: 12-03-2013, 06:18 PM -
parallel port address
By Dan Brown in forum Artsoft Mach (3 & 4)Replies: 6Last Post: 07-01-2010, 12:04 PM -
Laptop, ie no parallel port?
By tompsky in forum Laptops & TabletsReplies: 3Last Post: 11-11-2008, 07:12 PM -
Which USB parallel port emulator is the best
By bruce_miranda in forum General ElectronicsReplies: 1Last Post: 18-09-2008, 03:38 PM
Bookmarks