Alternative to PC based Cnc controllers

Martin, PM'd you.

Simon

Martin,

That all looks very tidy ... Hardware and Display

Two things leave me 'nervous' : MS Windows, and the 210page Software Manual.

**LINK**

http://planet-cnc.com/hardware/#products-hardware

Isn't that where this thread started ?

MichaelG.

Yes Micheal.

Because we are dealing with the hobby, small industrial user it takes in all types and also all types of budget restrains.

Everyone wants something different, they all have different goals. Some have far more time than money and some have far more money than time.

In giving various talks it soon became apparent that for some CNC instead of being a tool had become that persons hobby, the MK l leading up to make the MK ll and so on.

There will always be a niche for the guy with hardly any budget cobbling a setup from an Arduino and whatever else he can lay his hands on thru the PC based guys on whatever system THEY prefer up to the throw the cheque book at it guys and lets get it done.

This thread has been very interesting in that it's brought to light new options like the stand alone controllers and Martin mentioning Planet CNC. This was one I knew about but didn't know they had moved on.

In fact yesterday I downloaded the software and had a play, got stumped on lathe setup so fired a help request off on the forum which sort of explained the problem but I was able to sort it. My next question was are there going to be any more wizards for the lathe as they only do threading.

The answer was " Currently we are very busy with other software goals, but we are aware of the lathe feature importance."

Which in software speak means don't hold your breath. so as regards lathe, which at the moment is my area of interest Planet CNC is on the shelf with the rest of the unfinished software and hardware manufacturers.

So in a nutshell as long as this thread keeps people interested and looking it's doing a good job. These stand alone controllers have been on about 3 or 4 forums I visit and I did read on one but now can't find it that one of the big box importers was selling a CNC with one of these on but I can't find it and they may have been getting mixed up with a Siemens controller

There appear to be several different entry points into usbcnc:

• Mk3 9 axis board @ 219 Euros + VAT (about £240 shipped)
• Mk3/4 4 axis board @ 119 Euros + VAT (about £135 shipped)
• MK1 DIY PCB + PIC @ 21 Euros + VAT (about £32 shipped + supply your own components)
• MK1 Sky Studio MK1 version £42.29 (pennybuying.com)
• MK1 Chinese 'clone' @ £13-18 (ebay)

All of these options require a USB controller license (per board) from Planet CNC @ 69 Euros + VAT (about £73) or you are limited to 25 lines of Gcode, the software itself is free.

All of thes options will also require a PC/laptop/virtual machine to run the software - a cheap old laptop or netbook would probably be more than good enough based on the required PC specs.

The MK1 and Mk3/4 boards seems to give pretty much the same connectivity as a PC with a single parallel port, the MK3 board is required for anything that requires more inputs/outputs.

Many of the add-on boards look to be a little spendy - 22 Euros + VAT (about £23 + shipping) for an opto isolator, 10 or 16 pin header, DB25 connector, etc where there are less than £2.00 of parts on a board which itself would cost less than £1.00 - I don't mind paying a little for a quality item, but these prices are pushing it somewhat and the boards are easily within the realms of DIY.

A major plus is the use of an off-PC processor for the real-time processing, as previously mentioned, the PC is just a buffer for supplying Gcode and a user interface. As such they offer a similar solution/price point to Mach3 + Smooth Stepper or LinuxCNC + Mesa FPGA, with the added bonus that the hardware and software are from the same supplier and the PC specs don't really matter.

Downside is that you still need a PC an OS and an application.

Edited By Zebethyal on 04/10/2016 11:40:08

Only the first two listed will handle an encoder and there are features missing off the Chinese clones so be very aware.

Do the dedicated Chinese controllers have conversational or wizard features? I thought it might be worth asking on the PlanetCNC forum to see if we could get some of the more useful ones included.

Martin.

The Mk3 and Mk3/4 USBCNC boards also appear to use the same chip and mostly the same board layout, so you are effectively just paying to unlock the additional functionality in the software.

The Sky Studio MK1 has a few enhancements over the original MK1 and other 'clones' including optocouplers, separate power supplies, additional regulators and transient voltage suppression, but the same microcontroller, memory and pinout restrictions.

The Mk3 is a 9 Axis board, it also has a network connection option as well as quite a few more features like analogue inputs. I think the software is the same for all controllers.

Martin.

I'm a big fan of the LinuxCNC and Mesa approach, as:

1) the PC specs don't really matter, as the "real time, fast" thread for handling the olde LPT port is not required;

2) The Mesa boards seem to be about half the price of the Mach-3/4 based solutions;

3) They are used all over; this is the sw/hw combo that Tormach have moved to, for very good reason.

So, with an old PC, monitor, keyboard, (all cast-offs), and free software, and a not-too-expensive interface board, I can configure to my hearts content - adding switches, MPGs, spindle monitoring, DROs, "go back to zero" functions, incredible lathe threading, etc, etc. why not?

Does it take too much time to configure? IMHO, for me its 90% getting the machine made, 10% configuring the software, and none of these other boxes help with installing ball screws and steppers and encoders and...

Another JohnS

> 2) The Mesa boards seem to be about half the price of the Mach-3/4 based solutions;

I am not really seeing how the LinuxCNC + Mesa solution is half the price of a Mach 3 + Smooth Stepper solution.

Both require a PC of some sort, both will require steppers, stepper drivers, etc, so we will ignore all of that.

For LinuxCNC + Mesa, a base setup would be something like: 5i25/7i76 plug and go - $199.00 + shipping

(Trying to locate what Mesa hardware you actually need is a mission in itself! - the Mesa website offers little help in this regard, plus they claim a 6-8 week lead time from placing an order)

For Mach3 and Smooth Stepper: SmoothStepper $165.00, terminal board $29.55 + shipping

So from a hardware point of view there is nothing in it.

From a software point of view, LinuxCNC is free and Mach3 is $175.00 from ArtSoft (various discounted prices exist all over the web), although not everyone pays for a genuine license and many hacked copies exist (I am not advocating the use of hacked software - just stating what is available if you care to look), so yes, you can argue additional cost here, but not a particularly strong argument. for 50% cheaper from the home cheapskate point of view.

I agree that the board has additional connectors, but that is merely bringing out the relevant pins from the microcontroller to a header that were ignored on the cheaper board - PCB price difference negligable, additional headers, etc, again negligable since the 4 axis board actually has 2 different sets of header connections for both IDC ribbon and individual wire screw terminals.

Edited By Zebethyal on 05/10/2016 12:24:18

The 5i25/7i76 combo is way more than just the smooth stepper. The 7i76 is in all effects a break out board on steroids. 48 isolated i/o, 1 analog output, 1 high speed encoder counter (ttl/differential) 5 axis of stepper output and expandable.

If you can really even compare - the closest products to the smooth stepper would be

PCI 5i25 for $87.50

PCIe 6i25 for $107

Ethernet 7i92 for $87.50

(sorry - linuxcnc doesn't do any usb interface cards)

So - smoothstepper + mach3 is around $340 vs Linuxcnc with a 7i92 for $89.

sssssit---sssssit--sssssit (broken record)

The motion and realtime is all done in the computer with linuxcnc. The communication to the external interface boards are realtime (not buffered). This allows you to have some really cool access to the realtime subsystem. It allows you to connect the guts of linuxcnc any way you want.. Try to do that with dedicated motion controllers. You are stuck with what is implemented in them.

Lets be real here - for basic 3/4 axis machines that are nothing fancy - almost anything will work to control them. It comes down to what features above and beyond that you want. Linuxcnc is the 'above and beyond'. Gear hobbing? Large machining centers with tool changers and pallets? Threading and Tapping? kinematics? 9 axis tool length compensation? True Closed loop servo control? Open source? Integrated realtime PLC? Real time trajectory planning and path tolerance? and more and more..

sam

Charging the equivalent of €20 extra per axis and not even including the other additional features doesn't strike me as expensive or anything other than normal business practice. Actually, when you consider the potential increase in function of a CNC machine per added axis, it's peanuts - it's also no different to what other manufacturers do.

Having recently repaired the wife's 20+ years old mechanical sewing machine, I found a small piece of metal pressed into one of the plastic rotary cams used for selecting stitch styles. I could see it prevented the selector knob from turning fully, so I pulled it out. Doing so, instantly allowed the selection of loads more stitch styles.

If I remember correctly back to when we bought the machine, there were two versions of the same model... we got the cheap one (probably £150 cheaper) with fewer stitches, but it now seems the only material difference was that ours was crippled by the insertion of this blocking-piece.

Martin.

Edited By blowlamp on 05/10/2016 15:11:14

Pathpilot is based on linuxcnc but tormach did a bunch of stuff to personalize it. It is made to work with their line of machines. I have not played with it but have looked a bit in its guts. If someone thought it was linuxcnc and could configure it accordingly they where probably blind sided. Quite a few people now have worked though what needs to be done to configure it for other systems. It certainly isn't as easy as linuxcnc prime to setup. (it wasn't designed to be)

sam

(if you think linuxcnc is hard to configure - pathpilot is doubly so...)

Bob Warfield on the CNC cookbook site has some useful background on CNC control systems today:

**LINK**

Read it and it says nothing. Why is he even discussing Mach 3. It's dead in the water and has been for three years plus. No upgrades, no bug fixes and they are trying to drive Mach 4.

One thing he did mention though was the Siemens controller. Now Siemens have a deal with the Chinese and supply them the 3 axis 804 controller very cheap but this is for OEM fitting on machines for the Chinese market but they can be exported out of China. I was quoted about £1200 for a 3 axis system but it's locked down to one machine and preset at the factory, you tell them the parameters. However they are a very good and robust system.

The dearer Chinese controller mentioned on here are made / resold by many companies as they spot a market.

The original manufactures of these controller GSK have been making these for possibly 8 years and output must be in the tens of thousands id not hundreds of thousands but we never see much of them as they go into the Chinese domestic market on their CNC's. I have seen rows and rows of these making all sort of products that we are buying off our suppliers in this hobby.

Bobs article was originally posted back in 2011....

Note: I originally published this two-part series some time ago, and it has been hugely popular ever since. I recently went through it and added a lot of new information and updates. I am republishing so new folks will get a chance to see it and so folks that have already seen it can take advantage of all the new information.