Messages

1091

Mach4 General Discussion / Re: About G Code of Mach4 Demo

« on: August 30, 2021, 08:38:01 AM »

Hi,
the status message says Line0: Feature not supported.

Is the line of Gcode you've pointed at Line0.....I don't think so.

Post the whole Gcode file....we need to find Line0.

Craig

1092

Mach4 General Discussion / Re: About Mach4 Touch Module and Probing

« on: August 30, 2021, 03:44:04 AM »

Hi,

In Japan, G31 is described as a skip function.

I don't think that is correct, it is a 'Feed until skip'. This is for example the Fanuc21 interpretation which Mach4 follows closely.

G31   Feed until skip function           Used for probes and tool length measurement systems.

The command causes feed, at the prevailing feed rate, until an event, then skip the remainder of the move.

If X, Y, Z input the measurement signal to Mach4 before reaching the end point coordinates, Mach4 seems to measure without stopping.

I don't believe this is correct either. Ordinarily Machs Gcode interpreter would have several lines of Gcode in its buffer called look-ahead.
The trajectory planner can therefore do things like blend one move into the next without stopping, called CV mode. With a g31 block however
Mach cannot look-ahead because it has to make a move at the prevailing feed rate until the probe event, whereon the machine must
stop, the controller must report 'AllStopped' followed by the x,y,z location.....and abort the remainder of the move. It's this abort
the remaining move means that Mach cannot have further move instructions in the pipeline because otherwise there would be a time gap between
the probe event and the next scheduled move after the g31 block. This variable time gap would crash the motion controller which MUST
have time-continuous move instructions, even if the move instuction is nil, ie 'don't move' but it must get such an instruction every millisecond,
any gap in that stream of instructions will crash the controller.

Craig

1093

Mach4 General Discussion / Re: About Mach4 Touch Module and Probing

« on: August 30, 2021, 12:22:55 AM »

Hi,
Mach4 has a module called mcTouchOff, which as no doubt you have discovered allows you to automate such things
as touching off to a workpiece corner say, or a boss or some other feature, very handy.

The module is in fact a Lua routine which is viewable and editable and based on the repeated use of g31, the Gcode
probe command. Once you understand how g31 works you can easily write you own Gcode probing routines much like
mcTouchOff.

mcMapSurface is a wizard not a module. In this particular case the compiled code is published but not the source code.
Therefore you cannot view or edit it. What certainly is true is that it makes use of g31 to probe the surface at regular intervals
and thereby generate the data required to 'flatten the surface' in software. Even were the source code published I'm guessing you
could see regular Lua code for the probing routine and it would look similar to mcTouchOff  but what would not make sense is that
Machs trajectory planner must interact with mcMapSurface in order to modulate the Z axis, and that interaction will almost certainly
require C code rather than Lua.

You may have noticed that in Mach4CoreAPI.chm that nearly all APIs have both C syntax AND Lua syntax, but not so with the
mcMotion...APIs, they have C syntax only. As mcMapSurface is as much concerned with motion as it is about probing a surface
much of the wizard would be unrecognisable to anyone familiar with Lua.

The hierarchy is:
g31 probe command, enacted in realtime on the controller board,
mcTouchOff Lua code probing routines to automate the required g31 probe commands,
mcMapSurface a proprietary wizard that uses g31 to gather surface data and interacts with Machs trajectory planner to 'flatten' a surface.

Craig

1094

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 05:50:02 AM »

Hi,
kool, starting to make some progress.

A probe, a good one, should go open circuit if it touches and deflects in the Z axis AND/OR the X and Y axes as well.
As you now understand Mach is looking for, and will error out if it does not get, a probe event BEFORE the terminal
of the g31 move.

When I probe circuit boards I zero the Z axis on the top surface of the PCB. Thereafter the probing routine will move to a series of
preplanned x,y locations and probe in the Z axis. The moves are:

g31 z-2 f200
g0 z2
g0 x...y...
g31 z-2 f200
g0 z2
g0 x...y...    etc.

So the machine moves to a probe location, then probes  and expects, not only expects, but requires a probe event before the Z axis descends to
z=-2. It will stop, record the probe coordinates, retract to z=2 then rapid traverse to the next probe location.

Thus it would make no difference if I used this:
g31 z-20 f200
g0 z2
g0 x...y...
g31 z-20 f200

It would just mean that the machine will drive downwards until the probe event, lets say z=-0.054mm....but if the probe circuit were faulty it will carry on
and drive my probe tip to -20mm and totally wreck it. So there is distinct value in specifying a terminal g31 position so that a crash is not too catastrophic
should Mach/controller miss the probe event. On te other hand if I speciified:
g31 z-0.5 f200
g0 z2   etc
and at this particular location the top surface of the PCB is at -0.65mm then my probe would never detect the surface and throw an error such as you
have already seen.

A thorough understanding of how g31 works will help immensely when you go to write your own probing routines or try to diagnose faulty routines.

Craig

1095

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 05:07:26 AM »

Hi,
you should not be running the probing  routines....you can't get a regular g31 block to execute let alone the probing routine.

Execute MDI g31 moves only. Once you have got that mastered then move on but not before.

Jog to 0,0,0 then MDI g31 z-50 f10 and make sure to manually open the probe circuit before the move terminates.

Craig

1096

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 05:00:55 AM »

Hi,
will you just try to operate the manual switch BEFORE the g31 endpoint. The error message you are getting is BECAUSE
Mach is not detecting a probe event.

Craig

1097

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 04:39:14 AM »

Hi,

I haven't touched the probe manual switch.

THATS WHY IT FAILING....you have to operate the probe switch before it reaches the end.

Craig

1098

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 04:07:20 AM »

Hi,
No, the problem is that the probe event is not happening before the g31 block hits its end point.

There is (probably) no fault of the motor, no fault (probably) of the mcProbing module code, it's operator error,
you are not activating the probe button before the g31 finishes.

As an experiment try:
g31 z-5 f10
If the probe starts a z=0 it will take 30 seconds before the Z axis descends to z=-5mm and should give you plenty of time to hit the button
before the window of opportunity finishes.

Craig

1099

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 03:13:03 AM »

Hi,
you are using the Probing module, the fault could be in the code, or it could be your probe simulation set-up, or it could
be a machine fault.

Why don't you try writing some MDI code to test the g31 cycle, your machine and simulation procedure?
Once you have proven all those to your satisfaction THEN try running the module code. Note tat the Lua source code is
freely published for you to inspect, read, edit as you wish.

Mach4Hobby/Modules/mcProbing.mcs

Craig

1100

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 02:12:20 AM »

Hi,
if the controller does NOT detect a probe event BEFORE it gets to the g31 endpoint, its a fault.....end of story.
I'm not quite sure what you would expect.

Essentially what you are saying when you execute a g31 block like g31 z-5 f200 is 'advance to z=-5mm but expect to stop
before you get there', if you don't get the signal to stop, ie a probe event what do you want Mach to do? It did not detect the surface
it expected to find......thats a fault isn't it?

Craig