[Damon Hill]

New user, first reply:

There are some pretty wide ranging and specific issues in this thread EMC vs Mach3, but some of the issues I have questions on are more about linux vs windows based system issues.

Also I'm interested in the user freindlyness for a basic 3 axis stepper setup.

I intend to set a system up, but I will not be the primary user and need to have a stable and negotiable system I can easily train people to use and be productive with.

If issues arise, will troubleshooting either controller or system base come easier? Since this is the first system we will be setting in place that is not a major brand turnkey CNC system and more of a hobby/bench level cellular approach, I would like it to be a success and not a massive can of worms.

Anyone have some thoughts regarding these issues, it would be very helpful.

[andypugh]

If issues arise, will troubleshooting either controller or system base come easier?

Are you intending to use the parallel port for step generation?
If so, I don't think that there is much to choose between the two systems from a functional point of view, and AFAIK both have setup utilities for parport-based stepper systems that make it very easy.

Personally I am a LinuxCNC user (lawyers made us change the name) and consider it to be the more flexible system, but that might not be what you want in this case.
If this is for other people to use, they might be a bit less inclined to browse Facebook while milling with a Linux system. Looking a bit less like the PC they are used to might be useful.

If you want extra IO and hardware step generation then I think that the Mesa 5i25 / 7i76 combination is a much better (and cheaper) option than the Smoothstepper. But if you need to use USB rather than PCI then Smoothstepper + Mach3 are the only game in town. (AFAIK)

[dan dimock]

NOW WHAT SHOULD I DO?
I have a unit that I am driving with EMC2 and it has been missing steps bad so I got a new computer and the same thing is going on. I am just now getting into this CNC deal and had look at a lot of software. Both of the computer failed the test and I have slowed the unit
down as slow as it will go.
Will this happen with all software if I try one with the same computer?

[109jb]

NOW WHAT SHOULD I DO?
I have a unit that I am driving with EMC2 and it has been missing steps bad so I got a new computer and the same thing is going on. I am just now getting into this CNC deal and had look at a lot of software. Both of the computer failed the test and I have slowed the unit
down as slow as it will go.
Will this happen with all software if I try one with the same computer?

Need a whole lot more to go on than this. Losing steps can be caused by a number of things and can be computer related, machine related, or drive system related. Some questions to diagnose:

1- Are you running a real time version of linux?
2- what was the result of the latency check?
3- What are the settings in LinuxCNC
4- What machine is this on?
5- What kind of lead screws are you using (ballscrew, acme threads, rack and pinion)?
6- What size motors?
7- What kind of motor drivers?
8- What are the motor driver settings?
9- What power supply (voltage)?
10- which axis is losing steps?
11- When does it lose steps ( rapids only, all thetime, when cutting, etc)?

I'm sure there are other thing that would help diagnose, but that is the kind of information needed to diagnose the problem.

[andypugh]

I have a unit that I am driving with EMC2 and it has been missing steps bad so I got a new computer and the same thing is going on.

What do you mean by "missing steps"? If you just mean that the motors fail to respond to a step command when under load, or moving at high speed, then it is probably a mechanical problem (motors too small, or need a lower gear ratio).

You say that "both computers failed the test". If you mean the Latency Test, then there isn't a real pass/fail criterion. What numbers did you get?
There are very cheap boards that have great latency and work very well with LinuxCNC (as we are now obliged to call EMC2). The Intel D525MW is about $80 and has latency of about 10uS (10,000 nS) with a LiveCD install.

I don't know if switching to Mach will make your current computers output great quality pulse trains.

However, I suspect that your missed steps might actually be nothing to do with the computer or software. It could be electrical (unshielded motor wires interfering with step pulse wires) or Mechanical (motors too weak) or your power supply might be inadequate (what voltage are you driving the motors at, which stepper driver boards are you using)

This seems an odd choice of forum topic to post your query in, by the way.

If you are using EMC2/LinuxCNC then you might want to try a post on the lwww.linuxcnc.org forums.

[dan dimock]

My unit is a 24 X 30 inch size that I built, being a air craft welder, I knew that I could build the frame, so it is build very well as I used Thomson rails,
and has twin stews to drive the X axes and this is powered, as well as all axes by NEMA 282 oz/in motors.
I used Acme rods 10 threads per in. and all of these motors was wired by Probotix and it was tested in their plant and was set up to use the EMC software.They build the power supply and the drivers to fit the machine.
I do not know all the setting as it was set the way they told me by phone.
and now the computers are at the office of the gentleman who is helping me to run the test as outlined in the EMC2 software, as both computers gave the same type of problems. I called Probotix and was told that we needed to slow the unit down. After that was done it ran better for a while then it would, for no reason, run backward and it would go from 1/8 in to maybe 3/4 of a inch deep. Again I called Probotix and we reset the set up while I was on the phone with them. After that it still did not do right and then they told me it had to be the Computer. That is when I might go back to windows and try a software like mach3 as two computers
was costing me a lot.But from the help I got here I am going to order the
new mother board and try it.
So thanks for your help.
Dan

[andypugh]

then it would, for no reason, run backward and it would go from 1/8 in to maybe 3/4 of a inch deep.

The motors won't run backwards for _no_ reason, but it might be difficult to work out what the reason is.
With steppers the most obvious cause would be a problem with the "dir" wires, which could be a loose connection.
Another possibility is that the parallel port is being asked to supply too much current on the "dir" lines and whilst it works for a while, it might eventually overheat the pin-drive on the motherboard.
Parallel ports are generally a lot better at sinking current than sourcing it. How was your break-out board wired? Or if there is no BoB, how were the drives wired to the parport?

[dan dimock]

These are things that I can not answer. I have sent a E-Mail to Probotix
and I will forward this to them.
They have been super to work with, I am 77 and spend most of my time in a
power chair. I starter this over 7 years ago then got hurt and spent over two years in hospital and rehabs, just now getting back after this.
All of the electric items are inclosed in a metal case, and like I said before all
I did was mount the motors and plug it in.
I am going to call Probotix later today and talk to them again after they have had time to read the lasted post.
Dan