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Mach4 Homing Incredibly Slow Problem
« on: May 22, 2019, 05:02:04 PM »
Hi Everybody … first time posting on here and I really hope someone can help?

After lot's of Internet searching, I cannot find anything that resembles the problem I have.

- My machine is a CNC router with X and Y and Z axis.
- My machine has stepper motors (sanyo denki 1.8)
- My motion controller is a Hycon Integra 7866
- I am running Mach4 Hobby version
- Machine has 3 mechanical homing switches (one on each axis)

I managed to configure Mach4 so that I can jog each axis in the correct directions, at what seems to be a sensible speed.
When I click on the 'Home' button, each axis homes at what I consider to be a normal speed.

THE PROBLEM

However, when the axis hits the home switch, it goes past by about 5mm then very, very, very slowly ticks/counts down to zero before displaying 'referencing complete'.

The Y axis takes the longest (about 6 minutes)?????
Z takes about a minute
X takes about 4 minutes

.... so that's 11 minutes in total to home all axes!
 Surely that is not right?

Can someone please try to explain or suggest what I might have configured incorrectly?

Re: Mach4 Homing Incredibly Slow Problem
« Reply #1 on: May 22, 2019, 06:01:37 PM »
Have you adjusted the Back Off Speed ?
If it's a low entry, and you are in mm it will creep.
Re: Mach4 Homing Incredibly Slow Problem
« Reply #2 on: May 23, 2019, 02:58:21 PM »
Wow!!
Straight to it Overloaded!

That has sorted my problem right out ... and I really do appreciate your help ... thank you very much indeed.


I had no idea there was a back-off speed in the Hicon plug-in.
It was set at 0.4.
So, I tried a few numbers, and settled on 25 - which seems fine.


Now I need to set my work area limits.

Can I use the homing switches as limit switches?
Is there a 'best way' to set-up the limits on a machine like mine?
Please tell me if I need to open a new post with different topic?
Re: Mach4 Homing Incredibly Slow Problem
« Reply #3 on: May 24, 2019, 03:19:53 AM »
Hi,

Quote
Can I use the homing switches as limit switches?
Is there a 'best way' to set-up the limits on a machine like mine?

Yes you can combine home and limit functions in one switch ......but why?

If you combine the x++ limit switch and also make it your x axis home switch then WHEN HOMING  Mach will have to
ignore the switch activation as a limit and treat it as a home switch activation. So just while your machine is making
maximum extent excursions Mach has to ignore limits.....yeah right.....that's a good idea!.

If however you have separate limit and home switches no confusion exists. The limit switches are ALWAYS at the max
extents, any activation causes the machine to stop....no ifs or buts...always. Your home switches can be anywhere,
it is common to mount them just short of limits but they could in fact be anywhere in the travel zone. Using home offsets
allows you to define 'Home" as the lower left corner say but the home switches activate near the middle of travel in all axes.

It also means that you can use switches optimized for each job. For instance snap action microswitches have a defined
hysteresis and are superb home switches whereas proximity switches with ill defined hysteresis are not. They do make excellent
limit switches however as they can easily be mounted in such a fashion as not to be destroyed by an over-limit excursion.

Mach4 and your Hicon Integra have swags of spare inputs....why not use them and make your machine control robust?
In Mach3 when so many people had only a single port with only five inputs it was necessary to combine switches because of
the lack of spare inputs.....that is WELL BEHIND you now, so use the advantages that the software and hardware controller
offer.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 Homing Incredibly Slow Problem
« Reply #4 on: May 25, 2019, 01:13:29 AM »
Absolutely brilliant Craig …. a fantastic explanation … and very much appreciated!

I don't know why Vital Systems and/or Artsoft can't put explanatory details like this in their manuals? But perhaps the manuals would get convoluted.
Though, to be fair to Artsoft, they have provided this forum (which compliments the manual nicely).


Anyway, that's great Craig - thank you. I think I now understand why you would use purpose-specific/dedicated switches; and what type of switch is best for homing and for limmiting. And that it is probably not best (if you can avoid it) to use same switches for multiple purposes.


So if I understand correctly, I need to get 6 inductive proximity switches, and fit them onto my machine at each extent of travel - right?
Then I should wire them into 6 individual empty input terminals on my Hicon controller - e.g. P11/Input3,4,5,6,7,8.
Then configure the input signals (in Mach4) e.g....
P11/Input3 = Motor0--
P11/Input4 = Motor0++
P11/Input5 = Motor1--
P11/Input6 = Motor1++
P11/Input3 = Motor2--
P11/Input4 = Motor2++

.... and this will give Mach4 clearly defined limits on each axis, past which it must not travel the machine ?
Re: Mach4 Homing Incredibly Slow Problem
« Reply #5 on: May 25, 2019, 01:54:24 AM »
Hi,

Quote
So if I understand correctly, I need to get 6 inductive proximity switches, and fit them onto my machine at each extent of travel - right?
Then I should wire them into 6 individual empty input terminals on my Hicon controller - e.g. P11/Input3,4,5,6,7,8.
Then configure the input signals (in Mach4) e.g....
P11/Input3 = Motor0--
P11/Input4 = Motor0++
P11/Input5 = Motor1--
P11/Input6 = Motor1++
P11/Input3 = Motor2--
P11/Input4 = Motor2++

.... and this will give Mach4 clearly defined limits on each axis, past which it must not travel the machine ?

Yes, that would be ideal.

I did not go as far, but as it transpired I should have. What I did is have three home switches each with their own input.
Then I had all six limit switches, ordinary snap action microswitches all in series as limits, all to one pin.

Guess what, I had a moment, the X axis went over limit and the machine stopped as its supposed to. I then hit the jogX-
button, of course the wrong bloody way!!!! and wrecked the switch. If I had six limit switches each with their own input
my programming would have prevented me from jogging in the wrong direction and breaking things.

I learned two lessons, individual limit switches are good and switches which don't get wrecked are likewise good.

Individual limit switch circuits are the norm in industrial practice and with good software and controllers like Mah4 and the
Hicon there is no reason for us not to do the same thing.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 Homing Incredibly Slow Problem
« Reply #6 on: May 28, 2019, 06:34:57 AM »
Thank You Craig

Yes, I totally understand all that.
And I will fit limit switches (inductive) to each end of each axis of travel.
And I will use 6 of the many remaining Hicon inputs (one for each limit switch).

Really good explanation again Craig, and I really appreciate your help.
Thank You

NOW, I am going to ask about an appropriate MPG ... but I think it best if maybe I start a new thread.