Messages

4731

Mach4 General Discussion / Re: output on/off from same button

« on: April 24, 2018, 03:47:20 PM »

Hi,
sometimes it is easier to program a function, in this case a toolchange, without too many or even any interlocks. Once you have the function working THEN start applying
interlocks for safety.

If I understand your machine requires air pressure to run. Thus if you'll have an air pressure switch. It is a fairly simple matter to have the function not start if the air pressure is not OK, but what happens
if the pressure drops part way through the toolchange? I can well imagine you want your program to respond to that situation and that is very much harder. May I suggest that to start with do the easy
option and later decide whether the extra protection is really required and how you might do it.

As an example, say:
ISIG_INPUT10=air pressure OK
ISIG_INPUT11=tool present
ISIG_INPUT12=door closed

Then:
Function m6()
local hsig=mc.mcSignalGetHandle(inst,mc.ISIG_INPUT10)
AirOK=mc.mcSignalGetState(hsig)
hsig=mc.mcSignalGetHandle(inst,mc.ISIG_INPUT11)
ToolPresent=mc.mcSignalGetState(hsig)
hsig=mc.mcSignalGetHandle(inst,mc.ISIG_INPUT12)
DoorClosed=mc.mcSignalGetState(hsig)

If AirOK ~=1 then
         mc.mcCntlSetLastError(inst,' Air Pressure Fault')
         return          --If the air pressure is bad then message the fault then abort the toolchange by returning to the calling program
else
         -go to position
         -release tool
         -....
         -....       -- the body of the toolchange function
end
if (AirOK and DoorClosed and ToolPresent)==1 then
        m3
        mc.mcCntlCycleStart(inst)     -- if all the interlocks are OK THEN start the spindle and 'push' cycle start
end
end

Maybe a few ideas.

Craig

4732

Mach4 General Discussion / Re: Jerky dual axis movement

« on: April 24, 2018, 02:59:07 PM »

Hi,
glad you are making some progress.

My concern about cabling and the high frequency of pulses is not about interference, either interference leaking in to the step circuit nor interference leaking out of it
but rather that the signal may be attenuated.

Consider most coaxial cables have input capacitance of 60-90 pf per m. Thus two meters of cable between the PoKeys board and the drivers puts a load of 150pf on
the output of the PoKeys. The output is a low power TTL gate, excess capacitance could easily attenuate its output, further it would be worse at high frequencies than low.
A lot of very small moves as is often encountered in toolpaths in the vicinity of corners and the increase in frequency of the pulses might result in lower than expected
signal level at the drivers.

I'm not saying that it is the case but it could be. You will no doubt have noted that servo drives often specify an upper limit of 100kHz- 200kHz single ended signal but the same
drive will accept up to 500kHz when differentially signaled. Thus signaling a drive at high frequencies is not trivial.

Craig

4733

General Mach Discussion / Re: Time for a rip-out

« on: April 24, 2018, 12:19:42 AM »

Hi,
sorry just noticed a typo...the ESS does not have analogue inputs (ADC).

Craig

4734

Mach4 General Discussion / Re: how can i use my own lua libraries in mach 4 ?

« on: April 23, 2018, 11:10:00 PM »

Hi,
very kool! I'm not sure but LuaJIT is different to plain Lua.
Whether there is sufficent compatability to include it as a library in plain Lua I don't know.

How about putting LuaJIT in a module of its own? It would give you control of libraries etc without
bugging the hell out of NFS.

Craig

4735

Mach4 General Discussion / Re: how can i use my own lua libraries in mach 4 ?

« on: April 23, 2018, 10:29:42 PM »

Hi,
as far as I know all the standard libraries of Lua 5.2 are implemented.
Is the library you have have the same form as the standard libraries?

Craig

4736

Mach4 General Discussion / Re: how can i use my own lua libraries in mach 4 ?

« on: April 23, 2018, 09:13:59 PM »

Hi,
way above my paygrade...ah, hang on I don't get paid...LOL.

If I understand correctly Lua is a plugin to the core C/C++ program and thats where a library would normally be.
That would in turn require access to the plugin which is NFS property. They might be agreeable to a library addition.

Could you program (in Lua) the components/functions you want and put them in a module? Daz has done a good
video on modules in recent times.

Craig

4737

Mach4 General Discussion / Re: New people welcome !! Come in here and introduce your self!

« on: April 23, 2018, 03:16:26 PM »

Hi Greg,
welcome. At the current time Vital Systems HiCon external motion controller is the only external motion controller that has THC support for Mach4 whereas
just about all Mach3 external controllers and Mach3's internal controller, aka the parallel port, have THC support.

The HiCon board is very good but they start at $600 and you need to figure that cost in if you want to go Mach4. Mach3 still represents the cheapest way to proceed.
If you like a challenge and have some view to future uses the Mach4 is attractive, be aware ther is a brutal learning curve.

Craig

4738

General Mach Discussion / Re: Time for a rip-out

« on: April 23, 2018, 03:03:44 PM »

Hi,
I bought an ESS about 18 months ago and it been really really good. As you say having those extra ports is a luxury.

The PoKeys 57CNC is also worth considering, it has in addition to all those IO pins, slightly more than an ESS, it has ADC pins as well. So you could use a potentiometer say,
for spindle speed. The ESS does have ADC, great otherwise.

Craig

4739

Mach4 General Discussion / Re: limit switch config

« on: April 23, 2018, 02:49:06 PM »

Hi,
three switches would protect one end of an axis (three axes) OK.

If you used them as home switches however then you can use soft limits which would protect against out of bound excursions an all axes. Soft limits work well but
having three physical limit switches is an absolutely sure to provide protection.

Craig

4740

Mach4 General Discussion / Re: mcCntrlGcodeExecuteWait fail

« on: April 23, 2018, 02:42:59 PM »

Hi,
I think there was a change in a release that came out about 6-9 months ago.

Prior to that release GcodeExecuteWait() could not be successive statements and as a consequence multiple lines of Gcode had to be concatenated together.
The current releases allow successive statements.

Craig