Messages

1101

Mach4 General Discussion / Re: Mach 4 question

« on: August 28, 2021, 01:29:47 AM »

Hi,

In other words, I haven't turned on the manual switch, so I don't think the manual switch is the cause.

I think you may have found the problem.

As I posted earlier:
g31 z-5 f200      gets interpreted as:
g1 z-5 f200,       but would stop at a point where the probe makes contact, lets say z=-2.5mm. But what happens if the
probe DOES NOT make contact, then the machine will drive to z=-5mm WITHOUT a probe detection event and Mach will know
that the probe is faulty or for some other reason the surface was not detected and post a "ERROR: No contact with probe"
statement.

So the fault you are describing COULD be caused by a manual probe button NOT being activated (to simulate a natural probe event)
BEFORE Mach reaches it g31 endpoint.

Craig

1102

Mach4 General Discussion / Re: Mach 4 question

« on: August 27, 2021, 10:14:36 PM »

Hi,
in the early days (6.5 years ago) I tried using a manual switch to simulate a probe but did not have good results.

I did reach a conclusion as to why that was the case, but is just a pet theory of my own, whether it makes sense to you,
and even more importantly whether it's correct.....

I was trying to simulate a probe before my machine was complete, that is to say not all of the axes were operable.
Once all axes were operable and I instituted a good probe circuit probing has worked fine for me ever since.

I use Autoleveller, a software utility that probes a printed circuit board blank to measure its deviation (small, typically less that 0.2mm)
from flat, and thence modify the Z axis ordinate of the Gcode to isolation route the PCB. I have used it for years and probing a PCB blank
in ten or even hundreds of locations is commonplace, and I do it daily. I would have expected if there is a fault with Mach4 probing I would have
found it over the six plus years I've been using it.

The probing routine that you are using is not a native Mach4 operation, but is in fact a macro consisting of dozens of instructions to enact the
whole routine. ALL probing relies on the g31 code. If you don't understand how the g31 code works and its limitations then it should
come as no surprise that any macro built up of g31 blocks will fail.

An excellent description of the exact sequence of events when a g31 block is executed is given in Mach4Hobby/Docs/Mach4API.chm, look under
'Plugin Development/Probing' headings.

The shortened version goes something like this (mm units):
g31 z-5 f200
is interpreted as a more common g1 move from the controlled points current x,y,z location to x,y,-5 at a speed of 200mm/min
UNTIL the motion controller detects a probe event. On receipt of a probe event the motion controller stops, reports an AllAxesStopped
and then reports its x,y,z location, ie the probe position. The remainder to the Z axis travel, that is to z=-5mm is aborted.

That your probing routine passes a number of probe events it suggests that your motion controller and Mach4 must be co-operating
to successfully complete g31 blocks.

In practice all g31 blocks must be followed with a retract move, for instance:
g31 z-5 f200
g0 z5

This combination of moves will probe in the negative z direction until the probe event is detected, and once the position is reported back to Mach
then it will retract (at raid traverse rate) to z=5mm.

Now as the Z axis retracts you would expect the probe circuit to go open circuit right? Lets imagine that for some reason, fault or otherwise,
that the probe circuit does not open circuit. What is Mach to do? It has detected a fault....and as it may be required to do another g31
block in short order, has it not detected a fault that would preclude it from being able to do so?

When I was simulating a probe wit a button I believe that when the retract move was executing my motion controller was monitoring the
probe circuit and if it did not open circuit in some respectable time it would fault.

This is the basis of my pet theory.......but I have no evidence for it other than when I was trying to simulate a probe with a button, while
it would work with the 'probe closing event' it would often fail at the 'probe opening event' ie that I was not fast enough on the button.
What I did find is that when I got my Z axis working properly and a good probe circuit that kind of fault never occurred again. I presumed
that because the probe would open circuit within micro seconds of the Z axis retract block being executed that my motion controller was
happy enough that the probe circuit is operable.

As I say this is my own theory....whether its correct or not is up to you to decide.

Craig

1103

Mach4 General Discussion / Re: Mach 4 question

« on: August 24, 2021, 03:53:27 AM »

Hi,
if you're using Mach3 then good luck.

Craig

1104

Mach4 General Discussion / Re: Mach 4 question

« on: August 24, 2021, 02:18:18 AM »

Hi,
lets imagine for a moment that you wish to go the hardwired MPG route, and I have given some thought to doing so myself.
Every once in a while my USB connected pendant loses communication and the machine needs to be power cycled to bring it back,
a PITA....doesn't happen often but when it does that's when I think a hardwired pendant has advantages.

An MPG requires four wires, A+,A-,B+ and B-, unless you create a logic board that would reduce those four wires down to two,
namely Step/Direction, and that neglects the common return, so three wires in truth.

Lets say you had two three position rotary switches, each switch would require three wires (one common and the other two binary coded
for the three positions). Assuming the common return could be shared by the two rotary switches then you would require five wires for
the two switches.

Totaling the wires for this arrangement:
4 wires-MPG
4 wires-binary coded switch position (two switches)
1 wire-common return

This would require 8 spare inputs on your BoB/controller combination. Do you have 8 spare inputs?

If you want or need to economise on the inputs you could do it this way:
2 wires-Step/Dir derived from logic circuit of the MPG
2 wires-one for each of two buttons
1 wire-common return

This arrangement requires a small logic circuit be built into your pendant and that you write some Lua code to cycle through the axes
in the case of the ActiveAxis button and the jog increment in the case of the JogIncremnt button. This would reduce the number of spare inputs
required to four. Do you have four to spare?

Craig

1105

Mach4 General Discussion / Re: Mach 4 question

« on: August 23, 2021, 07:11:27 PM »

Hi,

So I have a question with regards to Mach 4. I want to use a pulse encoder generator (jog wheel) to control the jog movements of my axis. I would like it so if a button is pressed it activates the jog wheel for a specific axis(x) and if a different button is pressed it activates the jog wheel for a different axis(y). How would you or is it even possible to connect the pulse generator to Mach 4. Also, is it possible to edit the jog increments from buttons on a panel? Any help would be much appreciated.

All of these things are possible.

If you use an MPG that would have to be wired to your controller/BoB and then to Mach. You could have buttons OR switches to set the active axis and/or the jog
increment. There are some good examples but will still require that you do some Lua coding.

Another alternative is to use a pendant like a VistsCNC P1A, I've been using mine for seven years with Mach4. It has a two rotary switches for the active axis,
speed rate override, incremental/velocity mode, jog increment and more. They cost $160. No wiring, no programming, stands alone from your
controller/BoB so no loss of inputs......

Craig

1106

Mach4 General Discussion / Re: Mach4 XAxis Motor only vibrates and does not move - suggestions welcome :-)

« on: August 22, 2021, 06:47:09 AM »

Hi,
I think the buzzing is the stepper trying to reverse direction very rapidly, as if the Dir signal is changing state very rapidly.

Does your BoB have LEDs on the outputs? If so the Step output LED should assume a slightly dim condition when a rapidly changing signal
is applied, ie  a Step signal. The Dir oupt LED should change only if you jog in the reverse direction.

Craig

1107

General Mach Discussion / Re: mach3 goes to Z5 when pressing STOP

« on: August 22, 2021, 01:47:30 AM »

Hi,
try looking under the Safe-Z setting.

Craig

1108

Mach4 General Discussion / Re: Mach4 XAxis Motor only vibrates and does not move - suggestions welcome :-)

« on: August 22, 2021, 01:16:49 AM »

Hi,
sounds to me like you have the Step and Dir signals swapped over.

At your stepper driver temporarily disconnect the Dir signal. If the stepper/driver are good and you HAVE NOT accidentally swapped
the Step/Dir signals the stepper should move but only in one direction. Be prepared top Estop it.

If however the stepper/driver are good but you Have accidentally swapped the Step/Dir signals then I would expect the stepper to
do nothing...not even a sound.

Craig

1109

Mach4 General Discussion / Re: Mach 3 and 4 Electric Fall out

« on: August 20, 2021, 05:53:04 AM »

Hi,

The question that i have: Is Mach 4 the same, or are these problems fixed?

Overall Mach4 operates in very similar manner to Mach3, so no Mach4 has not, nor can it, solve that problem.
The issue is that Windows is not a realtime operating system and as a consequence all motion commands are buffered
by the controller, by sometimes as little as 50milliseconds but can be as much as 500milliseconds.

If a power outage occurs then the contents of the buffer are lost, and so Mach does not know exactly where the machine is,
which is also called 'loss of reference'. Thereafter you will have to Home the machine to re-establish reference, but that means real
trouble trying to pick up a job that you were part way through.

All Windows based CNC software solutions use the buffered motion model...in effect this is forced on them by the way Windows operates.
Industrial controllers however are realtime devices so that at any given instant the machine knows exactly where it is and there is no positional
loss at an unforeseen shutdown, excepting perhaps the axis motor deceleration due to inertia for which the motion controller can no longer track.

I can think of only one way that you could maintain reference across a power interrupted session would to be to use absolute encoders with
battery backup. This is more a hardware solution than it is about Mach or any other controller. Many servo manufacturers are offering absolute encoders,
sometimes so called multi-turn encoders and many with battery backup.

You will often see then advertised as 24bit, sometimes 27 bit and even 30 bit encoders.

Imagine you have a 24 bit multi-turn encoder, its possible to use 8 bits to record the number of complete revolutions from the home position and the
remaining 16 bits to record the angular position within that one revolution. Additionally should the power drop out the battery or supercap backup will hold
the data until power is restored, up to many months later. At repower the machine would know exactly where it is WITHOUT having to re-home.
I suspect that for the data to be accurate the power to the servo, or more importantly and correctly, the encoder assembly would need to remain
un-interrupted until the machine had decelerated or coasted to a stop, but within that exception the machine would retain accurate machine coordinates
across machine power cycles.

If I'm not mistaken Delta A3 series servos are of this type.

This is the only way to my knowledge that Mach4 can maintain accurate machine coordinates across different sessions, and I believe it is the exact same
method that pro controllers use also, but I'm not familiar enough with them to be 100% on that.

Craig

1110

Mach4 General Discussion / Re: Display Work Envelop button in the Tool Path Ops tab

« on: August 20, 2021, 05:15:05 AM »

Hi,

This begs the question, where are the src. functions, and the Properties etc documented?

To be honest I don't think they're are documented. My understanding is that they were never meant to be used outside of a testing and development
environment and would be superseded by regular .mc APIs. What information I can find on them is here:

https://www.machsupport.com/forum/index.php?topic=40051.0

Craig