[joeavaerage]

Hi,

I was hoping to home to the zero pulse of the servos - and actually even the Leadshine CL steppers I have in mind have zero pulse - but it seems UCCNC does not offer that feature(?).

I use Mach4 and have done for eight years (light years ahead of Mach3). It does have 'Index Homing', and was my intent years ago to use it. I use Omron roller plunger snap action microswitches for Homes and Limits.
As it turns out with them I can get 0.02mm repeatability while homing......and that is good enough, or at least the extra work and wiring required to use Index Homing is not high on my list of things to do.
I rather suspect that with good roller plunger microswitches you too could get 0.02mm or better, and in which case Index Homing is not really required.

https://nz.element14.com/omron-indus...15a/dp/1500340

I do rather suspect that I will use index homing for both the trunnion and fifth axis previously pictured. I'll want very accurate and repeatable way to zero the fourth and fifth axes.
I'm hoping that if I can zero them well and repeatably that I can still use the mill as three axis, with the vise still sitting atop the fifth axis. The majority of the parts I make a small and
mostly brass, aluminum and plastics. If the parts are small enough I would not have to remove the trunnion off the bed of the mill.....and that would be a major time saver.

Craig

[GeckoSub]

Hi,



I use Mach4 and have done for eight years (light years ahead of Mach3). It does have 'Index Homing', and was my intent years ago to use it. I use Omron roller plunger snap action microswitches for Homes and Limits.
As it turns out with them I can get 0.02mm repeatability while homing......and that is good enough, or at least the extra work and wiring required to use Index Homing is not high on my list of things to do.
I rather suspect that with good roller plunger microswitches you too could get 0.02mm or better, and in which case Index Homing is not really required.

https://nz.element14.com/omron-indus...15a/dp/1500340

I do rather suspect that I will use index homing for both the trunnion and fifth axis previously pictured. I'll want very accurate and repeatable way to zero the fourth and fifth axes.
I'm hoping that if I can zero them well and repeatably that I can still use the mill as three axis, with the vise still sitting atop the fifth axis. The majority of the parts I make a small and
mostly brass, aluminum and plastics. If the parts are small enough I would not have to remove the trunnion off the bed of the mill.....and that would be a major time saver.

Craig

Yes, there's a good video on home switches for hobby machines by JBWorxStudio on youtube and his findings are very much aligned with yours. He really liked the small Panasonic optical switch, too.
I am taking the liberty of attaching a screenshot here from his website that shows his results a bit more clearly than the video:


The reason I was thinking of the Metrols was because in the Philippines where I am now, we sometimes have power cuts so was thinking it would be great to have amazing home sensor accuracy to restart or continue a job, but I guess in reality I would just re-probe, re-zero from the vise corners or something like that. Though to square the gantry with the two Y-motors it would still be great to have some really precise sensors.

[GeckoSub]

How To Home A Rotary/4th Axis?

Hi,
(...)
I do rather suspect that I will use index homing for both the trunnion and fifth axis previously pictured. I'll want very accurate and repeatable way to zero the fourth and fifth axes.
I'm hoping that if I can zero them well and repeatably that I can still use the mill as three axis, with the vise still sitting atop the fifth axis. The majority of the parts I make a small and
mostly brass, aluminum and plastics. If the parts are small enough I would not have to remove the trunnion off the bed of the mill.....and that would be a major time saver.

Craig

This stirred my mind, thanks And a rotary does sound like a pretty near perfect candidate for zero pulse homing.

I had originally planned on having the rotary come way down the road, perhaps 6-9 months after the machine was up and running. But that might be changing. First of all, for the sake of getting the base right you guys urged me to really think the table layout and Z-height of the base through (thanks!). Also, I have found myself thinking about specialty tools, workholding, 2nd, 3rd ops, etc, at all sort of weird times a day already. I guess the bane of a (hobby) machinist in spe. Haha.
All this has firmed up the idea that the rotary will be incredibly helpful for the particular parts/product I want to make. So, now I am thinking the rotary might come as soon as I have an OK grip on the machine.
But how to home it?

If I stick to UCCNC, which I think I will, I see 2-3 options.
1). Indicate the part/rotary vise each time which I'd rather not do.

2). Use a switch, but I wonder how that works because I guess it would trip once per revolution, at least. Is it easy enough to tell enable it for homing/indexing and then disable it again right after? Or is that the sort of things macros are for? I have a feeling, just setting up UCCNC and wiring the machine will take plenty out of me and if this needs a macro, not sure how good I would be at that.

3). I think it may be possible to have the Delta A series do a zero pulse homing routine in the drive. I may be wrong, but I think that's one of the differences between the B and A-series. So, let's say the A series can do that, how would you trigger that from the software side. Is that another "dreaded" macro...? (I can get Delta A2 used too. A bit less than double what the B2 are, but still not too bad).

I may have left something obvious out

Also, I mentioned early in this thread that I had a 2 week, self-imposed deadline to send the base drawings off to the factory. The beauty of self imposed deadlines is that the guy who set it, wont hold it against me when they are moved....
And there's a cashflow issue, too. Haha. But as mentioned things are looking brighter on that front with the assignment I am about to fly out on. So, now the deadline for getting the base started and parts shopping spree is when the payment has come in + some days to finalize the base design if not done already by that time. In other words, no immidiate hurry. Maybe something like 3-4 weeks.

[joeavaerage]

Hi,
homing is a realtime operation, it has to be. The machine needs to respond to a home switch event within micro seconds. But UCCNC is running
on a Windows platform which is NOT realtime, ergo a home switch event being reported to UCCNC could take many milliseconds, then the PC/UCCNC has to make a decision and that
gets propagated to the motion buffer which could easily be several hundreds of milliseconds long. The around the loop delay could be several hundred milliseconds, way WAY WAY too slow
for Homing. No, UCCNC is not realtime and so cannot do homing. It is the hardware motion controller that does homing. Sure it does it with data from UCCNC but the motion controller
has to home autonomously. Thus there is no secret macro that will make this happen as the macro is within UCCNC and cannot enable realtime behaviour.

If you want index homing then you have to use a motion controller that supports it. By-in-large motion controller behaviour is not user programmable....so if it does not have a feature you can't put it there.
You could alternately use LinuxCNC which is realtime, and thus you could program index homing if its not already there

You maybe correct about the A2 series servos being able to home themselves.

The B2 series has digital inputs which can be assigned certain properties. There is one called CCLR (page 7-96 of the ASDA B2 manual) that clears the pulse counter. Presumably you could trigger this from the Z signal
of the encoder. I suspect with some care you and clever programming of UCCNC you could make a B2 series servo home itself to an Index pulse.

To be honest I think you are making a real challenge for yourself. If you require Index Homing get a CNC software/motion control system that provides that feature. Mach4 has it for example.

Craig

[GeckoSub]

Hi,
homing is a realtime operation, it has to be. The machine needs to respond to a home switch event within micro seconds. But UCCNC is running
on a Windows platform which is NOT realtime, ergo a home switch event being reported to UCCNC could take many milliseconds, then the PC/UCCNC has to make a decision and that
gets propagated to the motion buffer which could easily be several hundreds of milliseconds long. The around the loop delay could be several hundred milliseconds, way WAY WAY too slow
for Homing. No, UCCNC is not realtime and so cannot do homing. It is the hardware motion controller that does homing. Sure it does it with data from UCCNC but the motion controller
has to home autonomously. Thus there is no secret macro that will make this happen as the macro is within UCCNC and cannot enable realtime behaviour.

If you want index homing then you have to use a motion controller that supports it. By-in-large motion controller behaviour is not user programmable....so if it does not have a feature you can't put it there.
You could alternately use LinuxCNC which is realtime, and thus you could program index homing if its not already there

You maybe correct about the A2 series servos being able to home themselves.

The B2 series has digital inputs which can be assigned certain properties. There is one called CCLR (page 7-96 of the ASDA B2 manual) that clears the pulse counter. Presumably you could trigger this from the Z signal
of the encoder. I suspect with some care you and clever programming of UCCNC you could make a B2 series servo home itself to an Index pulse.

To be honest I think you are making a real challenge for yourself. If you require Index Homing get a CNC software/motion control system that provides that feature. Mach4 has it for example.

Craig

Sorry, def still making rookie mistakes. Yes, the controller, not the software, runs the homing!
I do like the ProbeBasic screenset for LinuxCNC, which basically looks "heavily inspired" by Pathpilot but maybe there's a bit of poetic justice in there as Tormach runs on Linux. Anyhow, not sure of the ins and outs, history and morality/legality of all this. I just liked that it looked "modern". But then I started reading and watching tutorials and LinuxCNC is a bit more than I am willing to dig into right now.
The controller for UCCNC does Mach(4?), too so it's not completely out of the question. I think Engineers Anonymous made a screenset that looks nice (there's a video on YT with a lot of crap talking). And yes, looks shouldn't matter, but if I have the choice, I vastly prefer a pleasant looking UI most other things being equal.

Anyways, back to homing. I don't mind at all a simple switch. Just wondering if it's easy enough to set up? I mean it would trigger once every revolution, right? So, is it easy to enable it for homing and then disable it again for the machining?