Quick Tip: IF you have Home/Limit Switches, here is an example and description on setting them up

All things related to the Centroid Acorn CNC Controller

Moderator: cnckeith

Roadstercycle
Posts: 18
Joined: Sun Dec 24, 2017 12:07 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: none
Location: Southern California

Re: Quick Tip: IF you have Home/Limit Switches, here is an example and description on setting them up

Post by Roadstercycle » Wed Dec 27, 2017 9:36 pm

cnckeith wrote:
Sat Dec 02, 2017 11:08 pm
Scoty i think you are confusing Part Zero location with Machine Home Zero location. these are two different zero points!
Machine Home by definition is machine ZERO. But that is NOT the same as Part (WCS Work Coordinate System) Zero.
When the machine is done homing the DRO (Digital Read Out) is displaying the distance the tool is from PART ZERO (WCS). (You can set the part zero location anywhere you want on the machine using the part setup menus F1 setup, F1 Part etc..)

Once the machine is homed out, pressing Alt D will show you that the machine coordinate system is at X0Y0Z0 when the machine is at the home position.
Jogging to the other end of the axis travel and stopping just before the axis hits a hard stop will produce the number on the DRO you need to enter into the software travel limit values in the wizard.

CNC programmers do NOT use the machine coordinate system to program parts. you use the Work Coordinate System to make parts.
so press Alt D again to switch out of machine coordinates back to the WCS and set your part zero position where every you need to on the machine to make parts!

oh.. and there is no such thing as having the home switch on the wrong side:-) you can put it on either end of the axis. no problem.

here in this old video when i had hair.. i talk about homing and part zeros..

https://youtu.be/mA41pUyONJM?t=6m23s
Keith, I just watched that whole video and it should be in a few places for people to watch for many different reasons not just homing. It is a fantastic wealth of knowledge. Anyone coming from Mach 3 or any other PC controlled controller that never used a industrial type controller would do themselves a great service to watch this. Yes it's old and no touch screen but it is great. I've been using Mach for years and now going to change over both my machines to Acorn and I am so glad I watched it. Answered tons of questions. Make it more available.

muibubbles
Posts: 14
Joined: Tue Nov 28, 2017 11:46 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: none

Re: Quick Tip: IF you have Home/Limit Switches, here is an example and description on setting them up

Post by muibubbles » Mon Jan 01, 2018 9:42 pm

Can someone explain the homing sequence (for a router table) for me?
The last controller I attempted was linuxcnc and the sequence was rapid to home switch, back off, then slowly index back to the home switch at a slower rate for better accuracy.

I've also read someone with limit + home switches has the sequence set up to rapid to limit switches then slowly back off to homing sensors.

Is this the standard sequence and is this how acorn handles it? or does it simply just stop once the sensors are triggered and sets it as home?
How do you change the speed at which the machine searches for home?

cnckeith
Posts: 605
Joined: Wed Mar 03, 2010 4:23 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: Yes
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: Yes
System Serial Number: none
Contact:

Re: Quick Tip: IF you have Home/Limit Switches, here is an example and description on setting them up

Post by cnckeith » Tue Jan 02, 2018 8:03 pm

what type of router? moving table? moving gantry? paired motor axis gantry or single motor?
homing a router is no different than homing a milling machine.
you have several options when homing any machine tool.
Simple Home and Home to Switch are the two big ones.
Simple Home just sets home where ever the machine is sitting. and is a reliable and simple way to do things , setup hard stops or marks and jog the machine to hard stop and then set home at that position.
"Home to Switch" is controlled by a G&M code program (called cncm.hom) so you have LOTS of choices on how you want the auto homing procedure to occur. Its does what ever the program tells it to do. cncm.hom is a text file so you simply edit the file with the commands you want to achieve the homing you desire.
Homing speed occurs at the slow jog rate for consistent homing results. if that's too slow for a large format machine, simply fast jog each axis close to the switch before homing and then start the home program, now the home program only has a short distance to go to hit the switch. you can also "park" the machine automatically at the end of the day close to the switches so that when homing out the next morning the machine is very close to the switches and you wont have to manually jog the machine close to the home switches everyday.

check out the operator manual on page 13-7 M91, M92, G92, M26, M105, M106 are all common M and G codes used in a cncm.hom. you can use them to build a cncm.hom program specifically for your machine.

muibubbles
Posts: 14
Joined: Tue Nov 28, 2017 11:46 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: none

Re: Quick Tip: IF you have Home/Limit Switches, here is an example and description on setting them up

Post by muibubbles » Tue Jan 02, 2018 10:58 pm

Thank you Keith that was very helpful I have a moving gantry router, 5'x14' so I will have to fast jog close to zero then home it from there.

How do I access the G&M code program? Is this simply opening a txt file that I have to manual write scripts? (I think this is similar to where I began to get lost in linuxcnc) Are there any videos on this?

When you say "slow jog rate" this is referring to the speed rate I assign to the "tortoise jog speed" button correct?

cnckeith
Posts: 605
Joined: Wed Mar 03, 2010 4:23 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: Yes
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: Yes
System Serial Number: none
Contact:

Re: Quick Tip: IF you have Home/Limit Switches, here is an example and description on setting them up

Post by cnckeith » Tue Jan 02, 2018 11:34 pm

muibubbles wrote:
Tue Jan 02, 2018 10:58 pm


How do I access the G&M code program? Is this simply opening a txt file that I have to manual write scripts? (I think this is similar to where I began to get lost in linuxcnc) Are there any videos on this? << Press "F6 Edit" on the main screen of CNC12 to edit the loaded G code program, or use windows and navigate to any .txt or .cnc or .nc program and right click and Edit the program. I use Notepad ++ (setup for g code editing see TB 294 http://www.centroidcnc.com/dealersuppor ... ds/294.pdf) >>>

When you say "slow jog rate" this is referring to the speed rate I assign to the "tortoise jog speed" button correct? << yes, you set that rate in the Wizard or inside of CNC12>>

muibubbles
Posts: 14
Joined: Tue Nov 28, 2017 11:46 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: none

Re: Quick Tip: IF you have Home/Limit Switches, here is an example and description on setting them up

Post by muibubbles » Mon Feb 05, 2018 10:19 pm

Thanks Keith, I will look into the file and study it some more!

The other day I was trying to wire up some NPN Proximity switches and got a little confused as the Acorn wiring diagram and other diagrams/info I came across only showed 2 wire connections (while the Proximity sensors have 3) With the help of marty I got them up and running so I just wanted to share how I wired them up for anyone who is more visual like me.

Brown- +24VDC
Blue- Common
Black- Acorn Input
Image

Hope this helps some of you!

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests