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Home switches wiring / setup

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06 Feb 2022 13:03 #234100 by remon_v
Hello,

For my MPCNC (Mostly Printed CNC) machine, I'm setting up LinuxCNC for the first time.
I'm pretty far with the basic HAL file and INI file.
The machine has 5 motors and 5 drivers (2 for X, 2 for Y and 1 for Z).

I have 4 cheap switches on my machine (2 for X and 2 for Y), also used for auto squaring the Axis:


Now I can use up 4 inputs on my 5 Axis BOB, but it's also possible to use 1 input for all the switches right?
Which one is preferred and does one has advantages over the other?

And is this possible with the switches I got and how to wire it?

Thanks in advance!

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06 Feb 2022 13:39 - 06 Feb 2022 13:42 #234102 by Clive S
I don't think it's possible to just use one input for all the switches.

You will need at least two (1 each for one side of the X and the same for Y)  You might be able to do it with 3 inputs.

It's hard enough as it is.   Personally I would go with separate switches for each one.

So if you are using a PPort you could use two of them.  Or use a Mesa card.

Others brighter than me might be able to guide you better. 
Last edit: 06 Feb 2022 13:42 by Clive S.

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06 Feb 2022 18:31 - 06 Feb 2022 18:32 #234143 by remon_v
Thanks for the reply, but I'm not convinced 

In the Stepconf there is an option 'all home' or something like that from the drop down menu when configuring your pins.

I have enough inputs, 4 for the home inputs and 1 for a touch plate or something. But then I loose the option to add anything.
Last edit: 06 Feb 2022 18:32 by remon_v.

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06 Feb 2022 20:42 #234171 by Todd Zuercher
There are 3 advantages to having separate inputs for All your home switches and limts. The first is easy identification of the source of a switch input, the 3rd is an axis may not have to be off of it's home switch before homing. The another is simultaneously homing is only possible with separate home inputs. So if you can live with homing one axis at a time, and make sure All axis are off the home switches before homing sharing isn't a problem.

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08 Feb 2022 10:04 #234334 by remon_v
Thanks for the reply. I wouldn't mind if simultaneously homing is not possible, but I think I will use 4 inputs for the 4 switches. I can always change it later, if I need another input.

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08 Feb 2022 15:05 #234343 by Clive S

Thanks for the reply. I wouldn't mind if simultaneously homing is not possible, but I think I will use 4 inputs for the 4 switches. I can always change it later, if I need another input.


As I said before and you were not convinced if you want gantry squaring you will need a switch on either side (they can also be used as limit switches) so in your case you will need 4 for two lots of gantry squaring\ plus one for the Z.

It would be helpful if you posted the hal and ini files.

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08 Feb 2022 20:46 - 08 Feb 2022 20:49 #234354 by Todd Zuercher
For squaring a gantry he would need a minimum of two inputs (4 is not required). If the gantry is the Y axis, X and Z could share inputs with them selves and or the Y joints. So Z and Y1 and X1 could share a home input and X2 and Y2 could share. Limits are not nessisary or can also share the home inputs. The two gantry joints in a pair are the only ones that must have home inputs separate from each other, but not necessarily separate from other switches.
Last edit: 08 Feb 2022 20:49 by Todd Zuercher.

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08 Feb 2022 22:40 - 08 Feb 2022 22:47 #234360 by Clive S

For squaring a gantry he would need a minimum of two inputs (4 is not required). If the gantry is the Y axis, X and Z could share inputs with them selves and or the Y joints. So Z and Y1 and X1 could share a home input and X2 and Y2 could share. Limits are not nessisary or can also share the home inputs. The two gantry joints in a pair are the only ones that must have home inputs separate from each other, but not necessarily separate from other switches.


Todd
I am under the impression that he has two gantries ie. X and y are both gantries.

From his first post:-

The machine has 5 motors and 5 drivers (2 for X, 2 for Y and 1 for Z).

I have 4 cheap switches on my machine (2 for X and 2 for Y), also used for auto squaring the Axis:

Last edit: 08 Feb 2022 22:47 by Clive S.

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09 Feb 2022 03:53 - 09 Feb 2022 03:56 #234373 by Todd Zuercher
Yes, for example to wire it using normally closed contacts using two input pins for the 5 joints, a wire would go from input1 to the X1 switch NC terminal, then from the com terminal to the Y1 NC terminal, then from that com to the Z NC terminal and from that com terminal back to the port or bob ground. Then input2 would be wired similarly chaining the switches for X2 and Y2 together. If additional limit switches are to be added they would simply be added to one or both chains.

If the switches are wired using normally open contacts then they would need to be wired in parallel instead of in series.
Last edit: 09 Feb 2022 03:56 by Todd Zuercher.

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09 Feb 2022 09:46 - 09 Feb 2022 10:22 #234379 by remon_v
Thanks guys for the replies, it becomes a bit more clearer now!I'll give some additional information.
Clive S is right, it is a machine with 2 gantries:


I'm not sure if the switch are NO or NC, it has a S, V and G input.
So should I wire X1 + Y1 and X2 + Y2 in series or parallel?
I have no Z homing switch (yet).

I have attached my INI and HAL file
Attachments:
Last edit: 09 Feb 2022 10:22 by remon_v.

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