[rebeldevil]

Hallo everyone,
I'm building my first DIY CNC machine and now, since 2 long days, I can say that I'm stuck on set up homing and limit switches although I've given my best in researching on the web.
One resource that given me some hints and confirmed that this should be something possible was this video:

https://www.youtube.com/watch?v=mbT9SSVoeZc&t=1309s

So, as stated starting from the minute 18, I'm using one single switch for both the "X--" and "X Home" signals, connected to pin number 3 like so:



When i "Ref All Home" and that switch is pushed, "Emergency Mode Active" is triggered and Mach3 stops homing.
As far as I've discovered, Mach3 should ignore the limit while homing, and reconsider the same switch as limit when the homing ends for all the axis, can you please confirm or dismiss that assumption, or tell me if there are other Mach3 settings to consider to make him behave like described?
I'm using a chinese "Novusun NVUM4-SP" USB controller.

Any help is really appreciated.
Vincent

[ger21]

It could be noise triggering the switch, or switchbounce.
It also could be an issue with the plugin for the Novusun card, as it's what handles the homing.
With the parallel port, you can increase the debounce setting and usually get it to work, but I don't know if that card has a debounce or noise filter setting.

[KH0UJ]

one question sir, do you really need the XYZ limits switches?

[rebeldevil]

It could be noise triggering the switch, or switchbounce.
It also could be an issue with the plugin for the Novusun card, as it's what handles the homing.
With the parallel port, you can increase the debounce setting and usually get it to work, but I don't know if that card has a debounce or noise filter setting.

Thank you very much for your answer.
Yes that are all variables that I've considered, but I'm using inductive sensors as switch and I think in that case switch-bounce is not involved anyway.
The Novusun card plugin could be the only one assumption that make sense at this point.
I've not a parallel port controller available in this moment but I'm waiting for one and will post some update as I receive it.
Thank you anyway Sir.

[rebeldevil]

one question sir, do you really need the XYZ limits switches?

Thank you for your answer Khouj, not really.
I just want to complete my machine with every safety device possible, as I'm not an expert I want to avoid or limit any incident chance.
Have a switch that behave as homing sensor until homing procedure ends, then also as limit should be very nice.

[rebeldevil]

Just to update my re-search on the topic, also the following video demonstrates that Mach3 should ignore the switch as limit while Ref All Home is running:

ArtSoft USA - Video Tutorials
(choose "Inputs and Outputs" from the left side menu)

The same resource is available here

https://www.youtube.com/watch?v=3Ychv0q38MY

At minute 8:14 the author Paul Campbell explains how the limit is ignored showing the Diagnostics panel and clearly illustrating how both X-- and Home Led turns on while referencing X axis without triggering the Emergency stop.

[imitheo]

Mine are also not being ignored. Have you solved your problem?

I configured my home switch to be a limit, my only limit.

When i press Ref All Home, my Z goes up, hit the switch, it homes, but it also triggers a limit switch.

I thought about making a vb script solution, to ignore the Z++ limit, BUT i feel that something is wrong
and it should be already ignored.

[stefan30]

Hi,
I have the same problem. I use one switch for limit and home. If I home the axis it runs into e-stop from the limit. Did you get a solution?
Thank you

[mactec54]

Hi,
I have the same problem. I use one switch for limit and home. If I home the axis it runs into e-stop from the limit. Did you get a solution?
Thank you

Have you setup both the Inputs plus the Home and Soft limits pages I see above they only showed the inputs being set, you have to go to the Home/Soft limits and set this as well

[stefan30]

Have you setup both the Inputs plus the Home and Soft limits pages I see above they only showed the inputs being set, you have to go to the Home/Soft limits and set this as well

Thank you for your answer. I have set up the Inputs in "Pins & Ports" and the also the Home and Soft limits page. I do a retro fit on a Cincinnati Sabre 1250. I use mach3 and CSMIO IP/A Controller. All is working great but the Home/Limit switch can not be shared. I always have to turn the inputs off for homing and then activate the limit switches again. My setting in the inputs is one input for each axis. per example input 4 for X++ X-- HomeX and so on. It is one Switch mounted in the middle under the machine Tabe and 2 Blocks to push the switch at the end of the table.
I don't know what is wrong. Is there a macro in the background that tells mach3 to ignore limit switch on homing process? Does this only work with "homing all axis" button or also on diagnostics page with single homing axis function...

Thank you

[mactec54]

Thank you for your answer. I have set up the Inputs in "Pins & Ports" and the also the Home and Soft limits page. I do a retro fit on a Cincinnati Sabre 1250. I use mach3 and CSMIO IP/A Controller. All is working great but the Home/Limit switch can not be shared. I always have to turn the inputs off for homing and then activate the limit switches again. My setting in the inputs is one input for each axis. per example input 4 for X++ X-- HomeX and so on. It is one Switch mounted in the middle under the machine Tabe and 2 Blocks to push the switch at the end of the table.
I don't know what is wrong. Is there a macro in the background that tells mach3 to ignore limit switch on homing process? Does this only work with "homing all axis" button or also on diagnostics page with single homing axis function...

Thank you

Strange I have one machine that is using a single switch for home and limit for each axes and it works fine, I don't know if different versions of Mach3 may work different, I will check the machine I have today, and see how I set it up and what version of Mach3 I used

[ger21]

Homing is handled by the controller. In your case, the IP-A. You might want to ask CS Labs if it supports what you are doing.

[stefan30]

Homing is handled by the controller. In your case, the IP-A. You might want to ask CS Labs if it supports what you are doing.

Ah... ok. That is good to know. I will ask CS-Lab Support and will write here what they say. Thanx

[joeavaerage]

Hi,
the CSMIO has lots of inputs so you could easily have separate inputs for home switches and limit switches.

With them combined when homing Mach has to ignore limits....so just when you are likely to have a fault it just the time when Mach
ignores limits???

Craig

[stefan30]

Problem solved!
"The CSLAB Support wrote: "Since the CSMIO/IP v1.07 software version there is a possibility to give the same input PIN as LIMIT and HOME. You should disable the "Home SW. Safety" option in "General Config" window of Mach3. With "Home SW. Safety" option disabled, the LIMIT signals are not monitored during homing."
I did this and it does homing without e-stop from the limits. After homing the hard-limits are working.

[joeavaerage]

Hi,
to my knowledge Mach and all the controllers that support it do the same.

When homing ALL limit switches are ignored. ONCE homing is complete THEN limit switches are enabled again.

Most homing operations involve driving an axis to its extreme travel.....just when you don't have limit switches. If you have a fault
you crash your machine because your normal limit protection is inoperative. Does that make good sense to you?. It does not to
me.

I have three home switches, each on their own input. The limit switches, all six of them, are hooked in series, and to one input.
The home switches operate about 3mm 'inside' the limit. When my machine is homing it is not necessary for me to disable the limits
and so just when I feel that my machine is vulnerable to a crash, ie driving towards a home switch (only just inside the boundary)
the normal protection limit switches offer is still there.

In the early days of Mach when everyone had a parallel port with so few inputs combining limits and homes was required, with controllers
like the CSMIO with all its spare inputs you don't have to do it anymore. If you read on the Mach forum the number of posts about
people struggling to get limits and homing sorted and on EVERY occasion they are trying to combine functions. All that confusion
for what.....to save a couple of switches or a few feet of wire???. One crash will cause more damage than the cost of all the limit,
home switches and wiring combined.

Industrial machines have 3 home switches, and six limits, all on their on inputs. If any of the limit switches operate the machine de-powers
instantly to comply with safety law, no ifs or buts. No turning the safety devices off while you do something under ANY circumstance.
It also means that the controller knows that for instance the X+ travel limit switch has operated then the controller will allow only X- jog
moves to bring it back into bounds. Combining limits as I have done precludes that thus I have to be VERY careful when I have a limit
event to jog my machine in the correct direction. Not ideal but it has been like that a while! 'There is no more permanent situation than
a temporary solution.'

Craig

[skrubol]

If you're doubling up home and limit functionality, your home speed should be set low enough that a crash will not cause damage.
If you're running servos, or have steppers with enough grunt to cause damage even at low speeds, you really shouldn't be doubling up switch duties.