Types of Limit Switches Used

[bigbigjimb]

On converting my Seig X3 Mill the one area that I have halted at is limit switches, it is an area that is not covered in any detail. It would be usefull to see photographs of other peoples setups and to find out what they have used. The areas I am interested in seeing ideas is the folowing:
1. Limit switches or proximity types used
2. Ideas for housing the limit Switches
3. What was used and how the wiring was run. ie. I am thinking of using small dia copper pipe to run the wiring back to the control box.

Jimbo

[Greolt]

This is what I did. Proved to be accurate, reliable, durable and simple.

I purchased a kit from Syil. I would not do that again but that is another story and not the point here.

It came with three of these "photo interuptor" switches.

They were pre wired with the apropriate resistor and conector.

That would be easily done and cheap. Just three wires and a resistor. Ground, 5v and signal.

These were mounted under the table and saddle as shown. Well protected under there.

Wiring was routed to BOB inside plastic loom tube and well secured to keep them from catching on moving parts.

Actuators were made to move into the slot and "interupt" at the appropriate time. There is no physical contact.

As I said these have worked flawlessly and accurately. Syil have since abandoned these I believe.

I don't know why but suspect users were not securing them and associated wiring properly.

I've had my X3 for a while now and would not bother fitting limit switches if starting again.

I know people will disagree but that is my opinion as a relativly long time user of CNC'd X3. Soft limits works great IMO

On the other hand I see homing switches as essential and if I didn't have them I would go to a lot of trouble if needed to fit them.

I do not have fixed homing or limits on th Z axis. Superflous IMO. I use a "Tool Zero Switch" device to set Z

Regarding limits. On many machines if they hit a hard stop at rapid speed then there is repairs to do.

If this machine runs into a hard stop it makes a bit of a clunk and no harm done. It does not happen with soft limits anyway.

It is also worth noting that if cutting a job and it hits a limit switch then steps are most likely lost. If it hit a soft limit it decelerates before and no steps lost.

Hope this helps. Greg

[bigbigjimb]

Greg,
These Photo Interupter switches where I get confused with them is that there is many types of them and as not being electronically minded I would not know what to order specification wise and also what value of resistor etc.

What is the difference between Soft limits and homing switches, If I am correct there is a facility to install limit limits and homing in most boards but which one of these does soft limits come under, Is this just terminology. and howv do you set up soft limits?

I am really a bit weak on this part of the conversion and have never really grasped it.

Jim

[Greolt]

OK well set the "photo interuptors" aside for the moment.

Soft limits are not switches at all. They are a setting in Mach3

Once you power up your machine you then do a "homing run" whereby the machine sets off and finds 0,0 position by using the homing switches.

Then Mach3 knows where it is in relation to that 0,0 position at all times. Mach only allows "machine coordinates" to be altered via "homing" or often called "referencing"

Then the "soft limits" can be used because Mach knows when the machine gets too close to the end of travel. No physical switch needed.

Watch the video called "Coordinates / Homing" on the Mach support site.

Greg

[bigbigjimb]

Greg,
Checked that out, i dont know why i never looked at it before, i will try it out and get used to it, that sorts the soft limits out for me
Thanks
Jim