Messages

7151

Mach4 General Discussion / Re: Parallel port not recommended???

« on: February 06, 2017, 12:08:07 AM »

Hi crchisholm,
if you are going to lay out some bucks for an external motion controller then you should consider whether it will do
all that you require both now and some way into the future.

The PMDX-411 is a great device but it has a limited number of inputs and outputs, one 'ports' worth. The PoKeys 57CNCd25 is
another great device but also limited to one 'ports' worth of IO. Both devices are well priced and a perfect fit for your 540.
They will offer somewhat more IO than your used to with GBRL.

For an extra $60 you can get an ESS which has three 'ports worth' or for similar money the PoKeys 57ECNC which has even more.
It occurs to me that if you are going to buy an external controller it makes sense to get one that has some extra capability that you
may well use in the years to come.

There are of course even more expensive alternatives as well, there always is!

Craig

7152

Mach4 General Discussion / Re: Connecting to Mach4

« on: February 05, 2017, 06:15:06 PM »

Hi rhtuttle,
not quite sure what you mean....

An 'application' do you mean another program like Notepad++ or Excel?

Getting Mach to load a Gcode file is reasonably straight forward. This comes from the API.chm:
mc.mcCntlLoadGcodeFile(
      number mInst,
      stringFileToLoad)
So if you have a string for the file you wish to load execute the API call and it loads...easy

If this is what you mean let me know and I will post some examples. In fact if you look in Mach4Hobby/LuaExamples folder you will find plenty.

Craig

7153

General Mach Discussion / Re: z axis adjustment on milling machine

« on: February 05, 2017, 05:36:59 AM »

Hi,
that is normal, machine co-ord zero at the top of Z travel. When you drive the Z axis done the machine co-ords are negative.
When you get to the surface that you wish to machine zero the Z axis work co-ords. Then a negative Z will take you below the surface ie
cutting and positive Z takes you above the surface.

Craig

7154

General Mach Discussion / Re: About the motors

« on: February 05, 2017, 02:53:16 AM »

Hi,
guessing these are 34 size steppers about 900 ozin?

Steppers lose torque big time when running fast, at 1000 rpm they are likely to have on 5% of rated torque.

Probably wise to say that max speed is 500 rpm. If you use 5mm pitch ballscrews then max axis speed is 5 times 500=2500mm/min.

You can experiment but this should get you close enuf to start with.

Craig

7155

General Mach Discussion / Re: Change Wiring

« on: February 04, 2017, 05:15:26 PM »

Hi,
just change one pair, keep the blue and red together and the green and yellow together, but swap the terminals
in which they go.

Craig

7156

Mach4 General Discussion / Re: Pc requirements

« on: February 04, 2017, 03:09:04 PM »

Hi Guys,
I use an Atom based single board computer and its video is built right into the CPU chip. It is a very low CPU power device and the integrated
video means that it falls WELL short of the recommendation but it runs Mach4 just fine.

It really does struggle if you load large Gcode files, it can take an age before it generates a toolpath picture but once it does it runs the code
fine. I have a licenced copy of Mach4 on my laptop as well, its an i7 machine with 16G of RAM. I have used it to run my machine but aside from
loading big files way way faster it makes absolutely no difference to my machine. My laptop has all sorts of programs loaded including CAD/CAM
which really need the extra grunt but I don't like running my machine with it, if any one of those programs runs or decides it wants an update
or similar my machine falters or stops.

The wee Atom doesn't have any programs loaded I don't absolutely need, it doesn't have an internet connection or networking enabled and
consequently Mach doesn't get interrupted which is exactly what I want.

Craig

7157

Mach4 General Discussion / Re: Parallel port not recommended???

« on: February 04, 2017, 02:45:54 PM »

Hi crchisholm,
you are correct, a Mach4 licence and a Darwin Parallel Port licence and you are ready to go.

The pulse streams required to activate your stepper drivers (in the 540) are generated by your PC when using a parallel
port. The computer does this by running a timer where it resets a counter and when it counts up to a certain number it generates
an interrupt and the program resets the counter and starts again and also issues a pulse to the parallel port. The timers available
in a PC CPU chip are pretty limited by comparison to microcontrollers suitable for controlling machinery. Microcontrollers have hardware
timers that count up, reset and issue a pulse without CPU intervention. A PC timer requires considerable CPU processing to issue a
pulse stream and are generally called 'interrupt driven' timers.

The downside is that PC CPUs use interrupts for lots of different purposes, a simple one is the realtime clock, it generates an interrupt every
100ms or so just so it can keep the clock on your screen updated. It also uses them to switch between different software threads which we expect
to run at the same time. If two or more interrupts happen at once one will have to be delayed while the other one is processed. As far as our
pulse stream goes it means one pulse is 'late'. This variance in pulse timing is a fact of life with a parallel port and is called 'timing jitter'. There
is a test program which tries to measure jitter and therefore establish if or how well a parallel port will operate.

Some PCs do a good job of running a parallel port with low jitter and some do not. Very powerful and capable PCs are not necessarily any better
than an old XP clunker. Laptops generally do a poor job. Some PCs can be improved by turning certain things off and disabling certain automatic
features. In most cases you cant have different programs running with Mach as one program will interfere with Mach and the regular pulse stream
is broken. The good news is that many PCs do work OK and tens of thousands of CNCers around the world still use the parallel port.

For PCs that wont run a parallel port or if you require very stable pulse streams thats where external motion controllers come into play. They have onboard
either or both an FGPA and a microcontroller which generate very high quality pulse streams and very very much faster pulse streams than can be generated
by a PC alone. The result is smoother motion and also means that the pulse stream can 'keep up' with highly precise servo encoders for which a PC cant.

I suggest you use a parallel port, its a good fit with your existing machine and at a later date add an external controller if you think it desirable.

Craig

7158

Mach4 General Discussion / Re: oiler woes

« on: February 03, 2017, 06:13:51 PM »

Hi Mark4,
something to be aware of, I noted that you put a wx.wxMessageBox statement in your PLC script. I have done the same thing and crashed and
burned. The problem is that the PLC script runs repeatedly and the MessageBox will too, requiring you click OK at each occasion. The machine is
effectively stopped while the MessageBox is active and so you only have 50ms before the machine generates another MessageBox and stops.
Worse is that the PLC script is in the screen set and you will not be able to open the screen editor to remove it and a backup profile wont help
unless you backed up your screen set as well.

Daz-The-Gaz told me about a way to go straight to the editor by starting Mach4 from the Windows Command line.

I've had this problem twice, once when I put a MessageBox statement in the PLC script and on another occasion when I put one in the Signal Script.
The PLC script runs every 50ms (default) and the signal script every time one of Machs many many signals change state. Both scripts can be expected
to run many times per second. If you want to put a message on screen as digagnostic/confirmation use mc.mcCntlSetLastError() instead.

Craig

7159

General Mach Discussion / Re: Upgrade liscence.

« on: February 01, 2017, 01:22:47 AM »

Hi,
can't answer all your questions but some.

Mach4 is a new and completely different program and requires it own licence, ie no upgrade from Mach3
Mach4 has a lathe screen set and instructions, I'm not familiar with Machturn but certainly Mach4 can be used for
turning.
Welcome aboard. The Forum both Mach3 and Mach4 sections are a real highlight of Mach, enjoy.

Craig

7160

General Mach Discussion / Re: Mach 3 vs Mach 4

« on: January 31, 2017, 01:43:00 AM »

Hi,
I go with mkullman, Mach4 does everything I need in a mill and I have added features I need. LUA was a bit of a hurdle, but getting there
and it is INCOMPARABLY better than CE. Just my opinion of course.

Craig