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Author Topic: Limits/Homing Wiring For Two Machines Using One Controller  (Read 1825 times)

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Limits/Homing Wiring For Two Machines Using One Controller
« on: September 27, 2013, 07:40:58 AM »
I am new to CNC and would like some help/information

I have two machines – a gantry type router [existing machine] and a milling machine  [new machine] that I am converting to CNC.
The existing machine uses a Gecko 540 and has a combined home switch/limit switch on X Y and Z. Three in total – all NC . Axis A is slaved to axis Y. All works fine

I have copied this profile to control for new machine and will adjust soft limits, disconnect the A and Y slaving etc, before connection. I intend to use the spare axis [A] as a rotary axis for gear cutting on the new machine [I’m a clockmaker] but as I’d like to use the Gecko 540 to be interchangeable for both machines I’m wondering of the best way of achieving this from a limits/homing wiring point of view

[1] For the router, connections are made to points 1,2 and 3 of the Gecko to control the limit/homing switches for Axes X,Y,Z and A. [there is a four pin plug from the controller enclosure – Points 1,2 and 3 and -vdc] It occurs to me that I will need to use terminal 4 on the Gecko  for the new machine to control the separate axis A. [Five pin plug from the controller enclosure [4 axes and –vdc] Presumably, when connecting back the existing machine [which only uses points 1,2 and 3] I will have the plugs incompatible with each other and the limits/homing will not work correctly?

[2] Having looked at the forum, some say that a limit/homing switch on the 4th axis is unnecessary. I’d like advice from gear cutters what is the recommended set up. Pros and Cons. Also, without a homing/limit switch on the 4th axis, what is the situation when you press the “home all axes button”

I would appreciate any help that anyone can offer - thanks

Offline Fastest1

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« Reply #1 on: September 27, 2013, 08:14:35 AM »
First , Yes the G540 can be used to run more than one machine but as you can see, there are difficulties.

When referencing or homing only one axis moves at a time, Mach knows which axis are moving and which direction. When the switch is tripped, it zeros the DRO and moves to the next axis. The reason I said this, is you could gang the limit/home switches to one pin if desired including the A axis.

Also when referencing an axis that doesn't have a switch (and or that switch is not enabled), that axis will reset to zero (or whatever value you have placed in (Home Off) in the homing/limits box.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: Limits/Homing Wiring For Two Machines Using One Controller
« Reply #2 on: September 29, 2013, 03:09:25 AM »
Thanks Fastest1 I thnk that as long as I know where axis 4 starts then this will be ok. If it can start at same figure each time then thats OK Thanks again

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Re: Limits/Homing Wiring For Two Machines Using One Controller
« Reply #3 on: September 29, 2013, 01:03:41 PM »
Just depends on the accuracy you need. I would generally think the graduated dial would be sufficient, however tying in an additional limit/home switch is easy enough ( though I procrastinated it for years and still managed to make a few things, like holes in my table and vise, I wish that part wasnt a joke!)
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)