Messages

151

General Mach Discussion / Re: Use Home Offset to square the machine?

« on: March 23, 2023, 07:32:43 PM »

Hi,
you are misunderstanding what Home Offset is.

When Mach Homes an axis advances towards its Home switch. When the switch operates the machine stops and backs up until the switch deactivates. Then Mach zeros
the machine coordinates for that axis....unless you have programmed a Home Offset for that axis. If there is a Home Offset Mach does not zero the machine coordinates
but sets the machine coordinates to the Home Offset. It does not move the axis at all, it just sets the machine coordinates to other than zero.

This would be useful if lets say you could not mount a Home switch exactly where you want, but could mount it 60mm 'inside' where you'd really rather put the switch.
When you use a Home Offset of 60 for that axis the machine will be Homed, but Mach understands that the actual home location is another 60mm away.

Note that Mach3 and Mach4 have always operated this way.

Where you are getting confused is that some motion controllers have the ability to back off some programmed distance from the switch. Its not that Mach does it,
but rather the motion controller. Not all motion controllers do it....but over a period of time most of them do so. PoKeys have done so for years and the ESS for about two years now.
You'll have to look in the motion control plugin to find the setting.....OR code it yourself....its only a simple G0 move after all. This is in effect exactly
what the motion controllers do.....its just that they do it automatically.

Craig

152

Mach4 General Discussion / Re: Script da mach3 a mach4

« on: March 23, 2023, 06:00:54 PM »

Hi,
when you want a macro or script to stop and get either a response or data from the operator you are required to use wxWidgets dialogs.
Talk about starting at the hard place first!!!!

wxWidgets is an open source software library that gives you 'windows' type functions. For instance you might want a file  dialog, that is to say a window
that opens with a file directory so you can choose a file to operate on. There are a huge variety of such functions....but I find wxWidgets the hardest thing to
use in Mach4. Note that wxWidgets is not written into Mach4, but rather that Mach4 uses wxWidgets as an imported library. wxWidgets is used by an absolutely huge number
of programs, of which Mach4 is just one....and a small one at that.

The documentation for wxWidgets is superb, it's written for geeks, by geeks and in 'geekese'....you'll come to hate it as I do. If you really want to build your own forms
the best tool to use is called wxFormBuilder. Its an Integrated Development Environment (IDE) and allows you to compose code....but is in itself quite a learning curve.

There are three approaches to this problem:
1) Roll your sleeves up and get stuck into wxWidgets documentation and download and install wxFormBuilder and learn the software as well as is required to achieve the result.
2) Cheat! Find another Mach4 macro that has a wxWidgets dialog that is similar to what you want and copy it. Then you'll have to modify it to match what you want, still a learning curve
but is exactly where I started.
3) Change the macro such that you do not require a wxWidget dialog, of if you do make sure its the exact same as some other dialog that you can copy verbatim.

https://www.wxwidgets.org/

Craig

153

Mach4 General Discussion / Re: MACH 3 to MACH 4 and USS TO ESS

« on: March 23, 2023, 03:29:02 PM »

Hi,

Typically you will have to tune them to operate more slowly with lower P gain, more I gain, and if available a dead band in order to be stable. Anilam did this on some of their older controls.

This is equivalent to reducing the bandwidth of the torque loop.

A modern AC servo has a torque loop bandwidth of about 5kHz, resulting in a velocity bandwidth of about 1kHz and a consequent position loop bandwidth of 200Hz.
The critical point is the you need the highest possible torque loop bandwidth, because that in turn results in the best possible velocity an position loop bandwidths,
with the position bandwidth being what we are interested in, where the 'rubber meets the road' so to speak.

Any backlash or non-linearity of the linear scale severely curtails the high frequency accuracy of the torque loop, say down from 5kHz to 1kHz. If I'm not mistaken those
Anilam systems had tacho-generators on the servo shaft? This was to stabilise the velocity loop and thereby retain sufficient bandwidth for the position loop.
So the torque loop would be say 1kHz, the stabilised velocity loop 500Hz for a position loop of 100Hz. A 100Hz position loop was considered pretty damned good
for many years, and would still be entirely adequate on any hobby machine today.

Today with the likes of the A2 servo you can have high bandwidth torque and velocity loops by virtue of the high lineraity and resolution of the rotary encoder BUT
also the ability to 'load sense' with a linear scale for example. Best of both worlds. All the top servo manufacturers seem to have models that have the dual sensing feature,
but they all command a premium.

I buy Delta B2's, a 750W example costs me $438USD plus shipping. a 750W A2 (basic L version) from the same supplier is $682, so a $240 premium.

I am still only scratching the surface of what the B2 offers without paying for even more that I cant use!

Craig

154

General Mach Discussion / Re: Newby converting to Mach4 from Mach3 and scared but doing it

« on: March 22, 2023, 10:17:18 PM »

Hi,

it would be Mach that would ask the axis to move to the switch and then back off. I am using an ESS but I would not be apposed to getting a new one if I needed to.

In a sense you are right, but remember that Mach issues movement instructions which end up in a buffer, many hundreds of milliseconds long whereas the motion controller
can do things immediately or at least within a few microseconds, near enough to immediately. For instance let say Mach was waiting on the Home switch to operate.
The home switch operates and then Mach would be signalled up to 25ms later, then Mach would issue deceleration moves and they would propagate through the
motion buffer, say another 180ms. It just takes too damned long, the machine would have crashed before Mach knew anything about it. For this reason the motion
board must do Homing autonomously. It reports back to Mach when its done, but the motion controller is what does the business. Mach (3 or 4) has always been this way.

I am going to assume you have HOMING and LIMIT switches independently of each other??

I personally have done that with my new machine. I have three independent Home switches and six independent Limit switches , each one on their own input. You don't have to do it this way,
but I did. My new mill does 25m/min so I decided I wanted independent Limits switches, and just so Mach is at no time confused three independent Home switches as well.

Can I assume what you are saying is I need to program in a BACK OFF PROCEEDURE in Mach4??

The ESS has a back off provision, although I've never used it. You could alternately program such a move so that it happens automatically, either has the same result.
Internally the ESS does the move  automatically just as you would program it.

Lastly do you know where I can find a video that shows you how to change the touch button to be automated like it was in Mach3 using the AutoTouchPlate?

There are example scripts that ship with mach that you can copy and adapt to your machine. I seem to recall Daz-the-Gaz released a video dealing with that, look up the video section
of the board. Daz's videos are a great resource for newcomers.

Mach3 and Mach4 are sufficiently different that some ideas in Mach3 are just not applicable in Mach4. There is  feature  in Mach4 called the Signal Library and the signal script,.....its a whole new way
of dealing with signals and puts Mach3 in the shade. There is a catch.....it will do your head in for a wee while, thereafter you'll be fine, but initially its just not that easy.

Craig

155

Mach4 General Discussion / Re: MACH 3 to MACH 4 and USS TO ESS

« on: March 22, 2023, 07:14:47 PM »

Hi,
there are servo drives that can accept a glass scale input in addition to the normal rotary encoder....but they are not common and command a premium over servos that have a rotary encoder
alone. For example Delta A2 series servos:

https://www.fasttobuy.com/ecmac10807rsasda20721f-delta-220v-750w-239nm-3000rmin-80mm-dmcnet-ac-servo-motor-drive-kits-with-3m-cable_p27766.html

This servo will use the rotary encoder for velocity and torque loops but can close the position loop on a secondary encoder like a glass scale.

In earlier times with analogue servos it was more common to use linear scales to close the position loop, however those servos typically had a tacho generator
on the servo shaft that was feed back to the servo amplifier to stabilise the velocity and torque loops. Such servos are now rare and fading away into history.

There are motion controllers like the Hicon and CSMIO/A that can close the position loop using a linear scale, but note they produce an analog output voltage for the transconductance amp,
not Step/Dir.

There are servo drives like the Gecko G320 for instance that accept Step/Dir input, with encoder feedback, but to my knowledge must be fed with a rotary encoder, rather than a linear encoder.
Any dither associated with the difference between a tightly coupled rotary encoder and a rather more loosely coupled linear scale will absolutely screw the torque loop bandwidth, and
once that's happened all bets are off.

Craig

156

Mach4 General Discussion / Re: Intermittant hesitations

« on: March 22, 2023, 03:34:13 PM »

Hi,
I have the occasional glitch like that but with an ESS.

I came to the conclusion it was akin to Run-out-of-Data. The ESS does alert you that is the case....but that warning can be suppressed also.
I assumed that I had suppressed to warning but was a fault of that nature.

A few months ago the problem became more persistent, even troublesome. Then I recalled my PC had not been turned off for about four months.
I shut the PC down, rebooted and the problem has gone away...almost. I make it a habit now to shut down the PC every month or so.

Craig

157

General Mach Discussion / Re: Newby converting to Mach4 from Mach3 and scared but doing it

« on: March 21, 2023, 12:19:38 AM »

Hi,

I have so many questions, but I will start with why in the world would Mach remove the Diagnostics tab in there screens??

The screen set is editable, so find the screen set that has the best Diagnostics tab in it, Copy and paste it into your current screen set.

The big question I have and has been beaten to death but I still cannot figure it out is why can I not get A) any of the axis to back off of the homing switch when I use the switch as a dual limit and home? B) if I disable the limits and just have the switches as home then all the axis back off except Z and I have to actually give it an offset to retract from the switch? C) why won't Z axis go to its work zero when called to but all others do?

Homing is a realtime procedure and it by definition handled by the motion controller autonomously. The questions you pose are actually about the motion controller behaviour not Mach4.

For example for some years it was possible if you were using a PoKeys57CNC to have the axis back off a certain distance of a home switch, but few, in fact none of the other motion controllers
had that feature. Over a period of time other manufacturers did so....but note, it was the responsibility of the motion control manufacturer to do so not Mach4.

Note this is different to Home Offset. That is a feature of Mach, and has been since the earliest days of Mach. When an axis homes it travels towards the home switch until the switch activates.
The machine slows to a stop and then backs up until the switch de-activates. Depending on the switch the back-up is only 1/2 a mm or so. The motion control reports to Mach that
the axis is now Homed, and Mach duly sets the machine coordinates of that axis to zero........unless you have programmed a Home Offset, it which case the machine coordinate of that
axis is set to the Home Offset instead.

This might occur because for instance your Home switch is 100mm from the end of the axis but there was too many things in the way to put it right at the end. So you would program the
Home Offset to be 100mm and when Mach set the machine coordinate it would set it at 100mm. So despite homing to a switch that was still 100mm away from the end when the Homing
procedure was finished Mach would still 'know' where the end is. That is what Home Offset is for.

But please note Home Offset does not move the machine anywhere, its just a numeric adjustment to the Homing routine. Various manufacturers call it by different things, but mostly some variation
of 'Back Off Distance'. But again note that this is in some ways redundant because all you had to do with a controller that did not have Back-Off, was to home the machine and then call a G0 Xnnn.
as the first move, and lo the axis would back off the required distance. All the manufacturers have done is to include that extra move command automatically....you don't even see it.
You could however replicate it...its not that hard.

C) why won't Z axis go to its work zero when called to but all others do?

If you look at the GotoWorkZero() function in the screen load script you'll see that it only includes the X and Y axes. If you want it to include the Z axis just put it in....but be prepared for some
major crashes!!! In fact if you go to do this will you let me know...I could do with the entertainment!!! I joke. The last thing you want is the Z axis diving down to the Work Zero, commonly
the surface of the material. If you made as much as a 1mm mistake in your Work Zero you'd drive the tool hard into the material.

As I say put that code in there if you like but remember you asked for it.

I've been using Mach4 for eight years, and I've never found it necessary to drive the Z axis down into the danger zone that aggressively. Nor have I found it necessary to have an automated
back off distance, the machine homes and sits there waiting for me to jog to a convenient work location. If I felt the need I would attach the back off movement command at the completion of the
Homing procedure and not bother my motion control with it at all. I suppose I could use my ESS as it has back off feature, I've never had need to use it.

Craig

158

General Mach Discussion / Re: loosing steps

« on: March 20, 2023, 07:12:32 PM »

Hi,
well then you'll have to download the Clearpath manual, its freely available, and install the set-up and tuning software on a PC, and
at the very least interrogate the firmware to establish how its been programmed. It may well be that the HLFB output has never been programmed
and that would certainly explain part of your issue. You can also interrogate the servo with the PC and find out things like Following Error.

Your friend has no doubt paid a premium to get a machine with servos.....now is the time to dig into that capability.

Craig

159

General Mach Discussion / Re: loosing steps

« on: March 20, 2023, 05:51:44 PM »

Hi,
how about just answering the question....have you programmed the HLFB? If so what is it programmed for?

Start at the beginning, then worry about the RJ45 cabling. Just changing things without any sort of plan is going to waste a lot of time and money,
start at the beginning and work your way through it....and it all starts with the HLFB.

Craig

160

Mach4 General Discussion / Re: Script da mach3 a mach4

« on: March 20, 2023, 02:36:59 PM »

Hi,
the problem with tool changers is that they are all different, what will work with one does not work with the other.

The scripts which are released with Mach4 are intended as examples. It may be that one closely approximates your machine so you can copy the script and
modify it to suit. The expectation that your are going to find a script which is exactly right for your machine is doomed to fail.

If you are going to write your own code you'll need:

https://www.lua.org/docs.html

Mach4 uses version 5.3 to my knowledge.

Have you checked out the Mach4 API? It is Mach4Hobby/Doc/Mach4CoreAPI.chm, you'll refer to that document again and again.

My own little contribution for ENUMS, return codes, pound variables and the like is here:

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

Craig