Centroid Community CNC Support Forum

Hi,

I have a Avid PRO4848 and I like to park the spindle in the rear right corner of the machine, but home to the front left corner. I currently manually jog it forward after parking it then start homing, but that is annoying. I'm trying to write a homing script that searches for a rear limit switch and then rushes forward to near the front before initiating the homing sequence. All of my limit switches are on independent inputs.

I've tried to do this two ways, first I tried to home to the rear, but CNC12 complains about having duplicate home/limits in the wizard. Second, I tried just looking for the rear limit switch with M106, but that just causes CNC12 to issue a limit fault and halt.

Is there a way to temporarily disable limit switch check from a macro? Or is there some other better way to do what I'm trying to accomplish?

..Jack

Why not just home to the right rear? Your machine zero can be in any corner. You can still put your part zero wherever you want (e.g. front left).

is this a gantry with a paired axis?
if so follow the auto homing instructions in the axis pairing manual to get things going. once you get it up and running the stock method you can go and make a custom mods if you want. etc..
https://www.centroidcnc.com/centroid_di ... _guide.pdf

cncsnw wrote: ↑Wed Jun 03, 2020 11:40 pm Why not just home to the right rear? Your machine zero can be in any corner. You can still put your part zero wherever you want (e.g. front left).

Hey cncsnw,

I suppose, lower left is what I'm used to. Wouldn't that make all absolute machine coordinates negative?

..Jack

cnckeith wrote: ↑Thu Jun 04, 2020 10:16 am is this a gantry with a paired axis?
if so follow the auto homing instructions in the axis pairing manual to get things going. once you get it up and running the stock method you can go and make a custom mods if you want. etc..
https://www.centroidcnc.com/centroid_di ... _guide.pdf

Hey cnckeith,

It is a gantry with a paired axis. I haven't attempted auto-squaring at this point to keep it simple.

The stock homing method works fine, I'm trying to go beyond that. I want to park it away from where I home, but homing from 48" away takes forever. If you remember to jog it forward manual before you home, works, but I'm looking for a single click automated solution. There's a limit switch back there, so I should be able to go find it, which let's me know I can blast forward 47" then slow down for last inch to do the homing search.

Does everybody home to the rear on large gantry router as cncsnw suggests?

..Jack

"park" is used at the end of the day to park the machine near the home position so it takes the shortest amount of time to home the machine in the morning. you can customize the park macro to park the machine in any order and any position to suit your application.

cnckeith wrote: ↑Thu Jun 04, 2020 4:48 pm "park" is used at the end of the day to park the machine near the home position so it takes the shortest amount of time to home the machine in the morning. you can customize the park macro to park the machine in any order and any position to suit your application.

Hey cnckeith,

I get the park idea, but I want to keep my bed clear (spindle in the rear) at the end of the day and still have it home to the front. Parking at the front so it homes quickly doesn't accomplish that goal.

Is there a macro command equivalent for the "Limit Switch Defeat" VCP button? I do not see one in the documentation, I thought there might be a parameter somewhere that I could possibly toggle.

..Jack

I suppose, lower left is what I'm used to. Wouldn't that make all absolute machine coordinates negative?

Yes, it would. But that has no impact whatsoever on how you write CNC programs or run parts on the machine.

Indeed, I've just changed my park position so the table is back left instead of back right. This means the MCS coordinates in X are all negative now after homing. As Keith says, nothing else changes. In the meantime I have more room to move around the machine near my desk.

You get a similar pain if you power off without parking. That can result in a very long, slow parking move, so I use the MPG to job the table close to home before homing, using a couple of marks so I can see how close I am. If I overshoot using the MPG, the limit switches kill the feed - about the only time they do anything. This is a good justification for getting one of the wireless MPGs!

cnckeith wrote: ↑Thu Jun 04, 2020 4:48 pm you can customize the park macro to park the machine in any order and any position to suit your application.

Is the park macro in the default cncm files? What's it called (or what's the file path)? Thanks.