Messages

941

General Mach Discussion / Re: I want a proper Mach3 licence instead of the Chinese issued version.

« on: December 30, 2021, 07:58:14 PM »

Hi,
the ESS is an external motion controller. All its IO are 5V logic level. You could hook direct to other devices like stepper drives, but its fraught. One small mistake
with the hookup and you've fried your ESS. A breakout board does not add anything in the way of logic or smarts but it does buffer the ESS IO and provides much better
connections for wires etc. As such I would consider a breakout board as essential.

The MB3 by CNCRoom is indeed a good quality board with a good balance of inputs and outputs, mostly 24V capable, and has features to control a VFD. Note however it is designed
and paired with an ESS, it will not work nearly as well, if at all, with another motion control board.

I used Homan Desgins MB02's (no relation to the MB3 of CNCRoom) for my mini mill. I had two of them. They are bidirectional single port boards, and they proved to be fantastic
and I used them for seven years. They are still only 5V input/output and had no relays or PWM circuits. If you wanted extra features I would use a handful of electronic parts and
add them to the basic board.

For my new build mill (about six months old now) I was using servos for which I wanted differential step/dir signaling, and 24V tolerant inputs and outputs to match the 24V
industrial norm to which my servos are built. I also wanted an extra circuit to turn on/turn off the electromagnetic brake on the Z axis.  I knew what I needed and wanted and
what I did not want or need, so I decided to make my own breakout board, in fact I split the one board into two.

The first board, or port 1 of the ESS has 10 differential (+-2.5V) outputs for up to five servos, only three equipped thus far, five Alarm inputs, one for each servo, and two 24V outputs,
an Enable and a Reset, which is commoned to all five servos.

The second board I elected to make input dominated, ie pins 2-9 of each ports 2 and 3 of the ESS as inputs. This gives me 26 24V sourcing (5mA) inputs, one relay output for the VFD,
a PWM output again for the VFD, and 6 general purpose 24V sourcing and sinking outputs.

All up it cost less than an MB3, but of course took a lot longer to make and test. I've been using it for about six months, and I'm really happy with it. I would if rebuilding change the PWM circuit I used,
I sort of rushed that. It works fine but I could do better....funny I recall my Mum saying that!

If you wish to make one I  could post the circuit diagram and board artwork.

The XHC pendant may still well be useful. smurph, one of the leading developers of Mach4 and a clever cookie, has written a plugin for the XHC pendants. I used a VistaCNC pendant for seven/eight years,
but it started to crap out, particularly in warm weather. It has worked well enough that I should just buy another, but what I did was buy a really top quality (2nd hand) MPG and make my own
pendant. I finished it about 10 days ago and its proving to be everything I wanted, but nothing that I don't.

I have had my ESS for seven years, and I have bought another four for various retrofits in the years since, and never had a failure, nor even a serious bug with an ESS. Quite frankly the cost of
an ESS is small potatoes....and I've never regretted buying them. My servos,  two 750W Delta B2s and one 750W Delta B2 with electromagnetic brake and three day DHL shipping from China
cost me $1900USD. Who bloody cares what an ESS costs.....it's still chicken feed when compared to the servos alone.

Craig

942

Mach4 General Discussion / Re: Maho Heidenhain Indramat Mach4 retrofit.

« on: December 30, 2021, 07:06:03 PM »

Hi,
depending on the age of your servos the situation could be different and worse than you suppose.

In the early days,and to be honest, I would think predates your machine, the servo did not have an encoder, but it had a tachogenerator, or a speed sensor, and that was
feedback to the servo amp and it assisted in the closing of the velocity loop and the controller (PID controller) took encoder, or more likely linear scale feedback and
used it to close the position loop. Then in later years the tachogenerator was replaced by a resolver, which serves a similar purpose to an encoder, but encoders were at that
time incredibly expensive and fragile.

When I went to University and studied Control Engineering, many of the systems I studied and very extensively experimented with, and was tested, TESTED, and TESTED
on were of this type. We could at that time really only dream of Field-Oriented-Control being practical.That was in the early 80's. By the 90's however encoders and microporcessors
had advanced that much that Field-Oriented-Control was feasible and by the late 90's was de-rigour in the servo industry.

Advances in microprocessors, encoders, fast power electronic devices has only ever increased since.

I can buy a microprocessor that can do  floating point single-cycle -multiply-and-add at 90Mhz, with a whole suite of advanced peripherals for rotating machinery control for $20!!!!
A few years ago that was unheard of. Likewise I can buy a 1200V 20A MOSFET for $5.00 that can switch all day at 100kHz...amazing.

If you do buy new servos you are in effect buying into this evolution of electromechanical devices, and while not for free, at prices which only ten years ago would have been
considered impossible.

Craig

943

Mach4 General Discussion / Re: Maho Heidenhain Indramat Mach4 retrofit.

« on: December 30, 2021, 06:07:23 PM »

Hi,

This machine has feedback from rotary encoders on the motor shaft which is backed up by linear scales =Closed loop in my understanding.

Note quite. All servos have a rotary encoder so that the servo drive, or PID controller, knows the servos angular position and can compare that to the commanded
angular position, and drive the servo to close the error between the two.  But we don't specify angular position, we specify '6.342mm from there' or '12.687mm absolute'.
In an ideal world you could convert any linear measurement into and angular displacement of a ballscrew. This relies on the ballscrew being lineraly accurate and no
backlash. Much expense is encountered to ensure that is the case, but inevitably there will be some variance between angular position and linear position, and that variance
will be the basic accuracy of the machine.

If however you have good linear scales then you can compare linear position to angular position, with usually linear position being the more accurate, and demand that the servo
alter position to minimise the linear error.

All Feild-Oriented-Control servos, normally called AC servos, and the current state of the art in servos, require a very accurate and immediate knowledge of the angular position of the servo
in order to operate, and thus MUST have a rotary encoder. What I have elluded to is that you can have dual loop control, where the rotary encoder is used in the torque and velocity loops, but
the load sensing encoder/linear scale is used to control the position loop. As I say this is the last word in machine position control. If you can have it ....you want it!!!
This scheme would maximise the excellent mechanical properties that your machine has.

Over the course of time it is servos and particularly servo drives that have advanced and result in the machines we have today. Your machine is well built and rigid and would compare favourably
to any machine made today in terms of mechanical accuracy and rigidity. What a modern machine has is a much more sophisticated CNC control....and less, surprisingly enough, about the controller
or PC, but the smarts built into the servo drives. In this example we are talking about the servo drive, a Delta A2 series, offering this dual loop feature. The PC/controller can and is in fact fairly
basic, its the servo drive that adds the state of the art feature and the increased resolution and accuracy that comes with it.

Now I'm not saying you could not get your existing analog servos (with rotary encoder) AND the linear scales to operate in the same manner with LinuxCNC, but unless you are an experienced realtime
programmer it would not be easy, whereas using suitable AC servos then its (comparatively) easy.

Craig

Craig

944

Mach4 General Discussion / Re: Maho Heidenhain Indramat Mach4 retrofit.

« on: December 30, 2021, 04:12:52 PM »

Hi,

The slides, bearings & ball screws are lovely. So the glass linear scales could go on Ebay & maybe pay for some of the new tackle.
The motors are German so it could be either way. I will measure later.

I think your idea to replace the servos is the best choice, as you say the rest of the machine is superb....and you really want to retain that.

You might want to reconsider throwing out the linear scales.

Amongst the features of modern servos is the concept of dual encoders. Each servo will have a rotary encoder attached to the servo shaft, per normal, and
is absolutely essential for Field-Oriented-Control servos but can accept a second encoder (or linear scale) attached to the machine, called 'load sensing'. It will accommodate
any lash or other non-linearity of the machine and is the LAST WORD in position control. This possiblity should be considered very seriously if you already have good linear scales

For instance my 750W Delta B2 series servos, with 160,000 count/rev encoder and NO load sensing, ie the entry level Delta servo is $435 (servo/drive/cables)
The 750W Delta A2 series, with a 1,280,000 count/rev encoder AND load sensing is $540. Thus you get that load sensing feature and a better encoder for about an
extra $100.

This would turn your old but mechanically superb machine into a very much more modern machine with state of the art position sensing and control. Sound appealing?

Craig

945

Mach4 General Discussion / Re: Maho Heidenhain Indramat Mach4 retrofit.

« on: December 30, 2021, 02:56:49 PM »

Hi,
as I posted earlier, yes it is possible to make Mach4 operate analog servos, but the extra hardware cost (Hicon or CSMIO/A) and that you would retain your otherwise obsolete
servos count against that course of action.

If you are dead set on retaining your existing servos then LinuxCNC/Mesa is the answer for you. You will have to accommodate the programming and tuning as best you may,
its a direct consequence of the choice to retain the old school servos.

Modern CNC control technology has moved very distinctly away from controllers that close the loop, ie PID capable, to distributed motion control. The PC or trajectory planner
issues numeric trajectory data to the various servo drives and each servo drive plans and executes it part of the overall motion. The communication protocols are numerous
but EtherCat, ProfiBus and CANOpen have come to dominate. If you were thinking about a modern controller then you'd be a fool to overlook these new control paradigms.

An open loop Step/Direction software solution like Mach4 is still a later generation than a PID capable controller, but not at the 'bleeding edge' like EtherCat. Having said that
Kingstar DO have a Mach4/EtherCat solution, and certainly worth investigating.

It all comes down to the choice as to whether to replace the servos or not. If you choose to replace then you go down one path, if you choose not to replace you go down another.
Post some pics and as many details about the existing servos and drives as you can.

If replacing the servos is on the cards you need to determine exactly what they are. I would guess that they are genuine NEMA sizes, in which case you want to restrict your search for
replacements to NEMA servos, as they would be bolt-in replacements. Delta servos are metric, and while very close to NEMA not identical so retrofitting them can be tricky
even if 'bang for your buck' favors them.

Craig

946

Mach4 General Discussion / Re: Maho Heidenhain Indramat Mach4 retrofit.

« on: December 30, 2021, 01:16:33 PM »

Hi,
Vital Systems produce the Hicon Integra motion controller which can be activated to control analog servos. With activations
it costs $1200.  I would not bother, but rather replace the servos with newer units, the two alternatives are cost neutral but
by replacing the servos you have avoided the possibility of one of the original servo drives from crapping out, you cant replace them.

CSMIO/A is another Mach4 ready motion controller that handles analog servos. If you were using Mach3 I'd say do it, it good quality and performance. With Mach4
not so much, its Mach4 plugin is buggy and CSLabs have gone right off the boil as far as fixing it. They have not released any fixes for over a year.
The CSMIO/A costs 600Euro. I find it hard to recommend to spend that sort of money only to get crap support from the manufacturer not matter
how good the controller is.

Craig

947

General Mach Discussion / Re: Mach Support Video "Probing Outside Corner Part 2 in probing"

« on: December 29, 2021, 09:39:44 PM »

Hi,

There are also operations that do not cause problems with probing.
Therefore, I think there is a problem with the program.

I'm sure you think there is a problem, so why don't you research the threads on the matter on the Mach4 board, you may come to a different conclusion.

Craig

948

General Mach Discussion / Re: Mach Support Video "Probing Outside Corner Part 2 in probing"

« on: December 29, 2021, 08:20:48 PM »

Hi,

There should be something wrong with the program (mc.Probing.lua).

That is incorrect, there is no fault with the probing module, but rather some motion controllers handle it better than others.

Craig

949

Mach4 General Discussion / Re: Maho Heidenhain Indramat Mach4 retrofit.

« on: December 29, 2021, 06:56:02 PM »

Hi,

1/ The machine has a closed loop positioning system which I believe is one of the things which make it so accurate & I would like to keep. It uses Heidenhain LS403 scales which claim to be 1 micron precision. It has Indramat axis motors with TDM & KDS drives.

Mach4 is an open loop CNC software solution. If you require the PC to close a position loop then Mach4 is not the right choice, you could squeeze it out with extra hardware but its
probably not worth the effort. LinuxCNC would be a better choice if the REQUIRE the PC to close the position loop.

Most modern servos loops are closed at the servo drive.

For example my 750W Delta servos have a 160,000 count/rev encoder. If I cause Mach to issue step pulses then the servo drive drives the servo to keep up. If it overshoots it will reverse the servo until
it accurate, ie position feedback. The pulses are from Mach4 are open loop, that is it tells the sevro drive to go 10mm say, and the servo drive /servo does it automatically with highly accurate position feedback.
The only time you'd ever hear from the servo drive is if for some reason, overload for example, the servo can't keep up, with any sort of luck hardly ever, I haven't had a servo overload or Following Error fault in many months.

So despite Mach4 NOT being closed loop it can an does control closed loop servos, and on my machine I have set the resolution at 1um, although it could be much greater if I wanted.

I suspect that the servos fitted to your machine are old school analogue servos, and require that the controller provide the PID control loop. Can you post some more details about the servos and drives?

My Delta 750W servos/drives/cables cost $435USD each.......so replacing your existing servos might be an option,not cheap but would be a very direct and useful retrofit. It would mean that you do not have
to program a controller to provide PID functionality, and then tune the PID loop, no mean feat. My concern is that if you elect to reuse the existing servos you could very well get into the situation that the technical
skills required to do so are beyond you.....and that would constitute a major waste of time and resources. Replacing the servos with modern AC servo/drives is still quite a challenge but much easier that trying
to resurrect the old ones.

Just to give you some context....lets say you went with Mach4Hobby:
Mach4Hobby License  $200
Ethernet SmoothStepper motion controller $180
C25 breakout board   $40
3 x Delta 750W B2 series servo kits (servo/drive/cables) $1305
TOTAL  $1725

I'm not in any way suggesting that you'd have to go with this suite of components, it just a ballpark type guide.

A LinuxCNC alternative:

LinuxCNC free, open source
Mesa control board $200
Brain power to program it???
TOTAL $200

Thus you can see that LinuxCNC is very much cheaper because it allows you to resue your servos, whereas the cost of the Mach4 option is dominated by replacing the servos.

Craig

950

General Mach Discussion / Re: Mach Support Video "Probing Outside Corner Part 2 in probing"

« on: December 29, 2021, 05:52:21 PM »

Hi,
This post should be on the Mach4 General Discussion board, no doubt tweakie will shift it in due course.

The problem you describe is not a fault, its just the way some controllers handle a G31 error.

It is common practice when generating automatic Gcode to use G31 as a regular move rather than G1. This is because if the probe accidentally touches
something the machine will stop rather than carry on until the end of the normal G1 move and crunch the probe. It like a safe way to move somewhere
without damage.

What happens if however you code G31 X20? The machine will travel at the prevailing G1 rate to X=20, if it does not contact something along the way.
If it gets to X=20 WITHOUT touching something it will report an error, ie 'No contact with Probe'. Some controllers will just sit there and sulk, there is an error
that needs to be sorted, whereas other controllers carry on.

There are a number of posts on the Mach4 board that cover this.

Craig