New setup with Mach3 - Limits work, homing doesn't

[journeyonline]

Hello Group,

Not sure what I'm doing wrong. I have my limits working ok all wired in series to a hobby cnc board using pin 1 and pin 11. I was told you can use the same switches to home and limit. But I can't figure out my setup. I get lights when the switches are pressed ok on the diag screen, but when I activate my limits and home together I get a message that my switches have been pressed. Not sure what is going on here. I have watched the mach video on limits, and did a lot of reading in the past week, but still no luck. Any one got anything to try? If you need more info just ask.

[ger21]

Do you have 2 switches on each axis? And all are wired in series? And you want to use 3 as home switches as well? Need a little more info on how you have them wired. And what do you mean when you say "activate them together"?

[Torchhead]

You can indeed use the limits as homes. If you wire them in series they have to be normally close (NC) and wired so that the activation of any switch breaks the chain. Since it's normally closed you have to set the inputs to Active High...in other words when a switch is activated the input to MACH goes open and it appears as a high signal in the pins.

The homes can be defined to the same pin because they happen in a defined sequence. Z followed by X followed by Y. The first switch that opens in the string triggers that respective home (hopefully it's the swtich for that axis (:-)) and then it backs off (which closes the swtich again) and the next axis strokes it's switch, etc

This lets everything use one set of inputs. Another method is to provide NO switches for each home (requires a different input to MACH for each one) and then have the limits wired in series as NC into one more input.

Main thing is to get the polarity right in MACH on the inputs. For normally closed it should be Active High show up when you hit any of the swtiches in the chain. You don't need but one limit input defined in MACH because a limit event does the same thing on any axis: goes to e-stop

Tom Caudle
www.CandCNC.com

[journeyonline]

Ok I have 6 limit switches total 2 for each axis. One one each end, the switches are all wired to Normally closed. I set this for my home switch settings. When I check the diagnostic screen in mach3 it show yellow lights when I push a switch. I do not have any check boxes selected for the active low, so I think this means they are set to active high.

Now for the limit part when I turn on the limit switch + or - it just says a limit switch has been triggered.

Hope this helps and thanks

[ger21]

How are you using pins 1 and 11? 3 switches each?

[journeyonline]

I have all 6 switches wired in series with then connected to the hobbycnc board with pin 1 and pin 11.

Hope this answers your questions good enough.

[ger21]

Is one of those pins a ground? I don't have a HobbyCNC board, but neither of those are usually ground pins.

I don't know which model you have, but they should probably be wired from pin 11 to the GND connection.

http://www.hobbycnc.com/images/4aupc_6.jpg

[journeyonline]

Yes, the pin 1 is ground. From what I 've read and it does light up the home switches when i check the diag screen.

[ger21]

What model board do you have?

[journeyonline]

4 axis rev 2 board. I have the wires running into pin 11 and ground on the connector.

[ger21]

Their website says pin1 is not connected, so I'm not sure. I'd disconnect all the switches, and start with 1 limit switch. Get that working, then add the home to the same axis. Keep adding switches and checking them one at a time. There are too many variables when nothing seems to work.