Homing issue in 4.14 <answered>

[Doc1]

I am using the same Switches, and cannot modify the mounts very easily right now ,
other than changing the wiring to home all, is there a fix for this yet?
Upgraded from 4.12 which worked great to the 4.14 upgrade and doesn't home at all past z axis.
how do I revert back to 4.12 easily to get the machine back up and running?

[Doc1]

I found how to revert back to 4.12 !
Up and running !
Will be watching to see if this problem gets fixed ,so I can upgrade to 4.14
Thanks

[cnckeith]

the fix is to setup the switches so they clear within one turn of the motor or .25" or 6.35mm which ever is greatest.
if you have switches that take more than .25" or 6.35mm or one turn of the motor which ever is greatest to clear once they have been triggered cnc12 is not going to make it thru the home program.

home switch clearing amount was added in v4.14 to stop an axis from traveling the entire way across the table and crashing into the other side if a home switch did not clear for what ever reason. the .25 " or 6.35 mm or 1 full revolution which ever is greatest is hard coded. these are reasonable numbers, if your machine needs more than .25" of axis movement to clear a home switch time to get a new switch or change the trigger geometry.

[swissi]

I have to admit that my statement that 6.35mm should be enough to clear every switch was wrong. I do have some of these switches pictured earlier by humbug but never used them because I went with proximity switches at the end. I just checked one of these switches and it just occurred to me how horrible they are. If you just extend the arm a little you can get easily past the 6.35mm and I also noticed that (at least on the once I have) the contacts are not always giving a reliable closing signal.

These switches are definitely not for machines with limited travel as you are wasting a lot of travel just for homing.

-swissi

[cnckeith]

I have to admit that my statement that 6.35mm should be enough to clear every switch was wrong. I do have some of these switches pictured earlier by humbug but never used them because I went with proximity switches at the end. I just checked one of these switches and it just occurred to me how horrible they are. If you just extend the arm a little you can get easily past the 6.35mm and I also noticed that (at least on the once I have) the contacts are not always giving a reliable closing signal.

These switches are definitely not for machines with limited travel as you are wasting a lot of travel just for homing.

-swissi

agree'd! don't use big ol clumsy limit switches made for a conveyor belts.... use decent switches.. a good $20- 35 prox switch can be quite accurate so there is no need to try and use terrible switches not made for cnc.


if you really must use limit switches that have a clearing travel of more than a 1/4 of an inch..you can create a custom home program
like this..


; wire switches into one input..use "HomeAll"
; or
; wire switches into individual inputs.. then use "FirstAxisHomeOK", "SecondAxisHomeOK", "ThirdAxisHomeOK" etc..
; then "write settings to CNC control"..then edit the cncm.hom program to look like this below...
; edit the M106 or M105 to change homing direction
; edit the G91 X/Y/Z values and sign so it backs off the clear the amount you need.
; now set the wizard to "Custom Home Program" so it doesn't overwrite the custom home program
; and be sure to setup travel limits


N100 ;Check for an open home switch
;First axis minus and plus
IF #21301 == 0 THEN #111 = 9 ELSE #111 = #21301
IF #21401 == 0 THEN #112 = 9 ELSE #112 = #21401
IF [#20101 != 78] && [#21301 != 0] && !#[50000 + [#111]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20101 != 78] && [#21401 != 0] && !#[50000 + [#112]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20101 != 78] && [#21301 != 0] && !#[50000 + [#111]] THEN #101 = #101 + 1
IF [#20101 != 78] && [#21401 != 0] && !#[50000 + [#112]] THEN #101 = #101 + 1

;Second axis minus and plus
IF #21302 == 0 THEN #111 = 9 ELSE #111 = #21302
IF #21402 == 0 THEN #112 = 9 ELSE #112 = #21402
IF [#20102 != 78] && [#21302 != 0] && !#[50000 + [#111]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20102 != 78] && [#21402 != 0] && !#[50000 + [#112]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20102 != 78] && [#21302 != 0] && !#[50000 + [#111]] THEN #101 = #101 + 1
IF [#20102 != 78] && [#21402 != 0] && !#[50000 + [#112]] THEN #101 = #101 + 1

;Third axis minus and plus
IF #21303 == 0 THEN #111 = 9 ELSE #111 = #21303
IF #21403 == 0 THEN #112 = 9 ELSE #112 = #21403
IF [#20103 != 78] && [#21303 != 0] && !#[50000 + [#111]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20103 != 78] && [#21403 != 0] && !#[50000 + [#112]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20103 != 78] && [#21303 != 0] && !#[50000 + [#111]] THEN #101 = #101 + 1
IF [#20103 != 78] && [#21403 != 0] && !#[50000 + [#112]] THEN #101 = #101 + 1

;Fourth axis minus and plus
IF #21304 == 0 THEN #111 = 9 ELSE #111 = #21304
IF #21404 == 0 THEN #112 = 9 ELSE #112 = #21404
IF [#20104 != 78] && [#21304 != 0] && !#[50000 + [#111]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20104 != 78] && [#21404 != 0] && !#[50000 + [#112]] THEN M225 #100 "Home switch tripped!!!\nPlease clear before Homing.\n\nPress Cycle Cancel to end Homing"
IF [#20104 != 78] && [#21304 != 0] && !#[50000 + [#111]] THEN #101 = #101 + 1
IF [#20104 != 78] && [#21404 != 0] && !#[50000 + [#112]] THEN #101 = #101 + 1
IF #101 != 0 THEN GOTO 100


M106/Z P3 F30 ; move to Positive limit wired into input #3
G91 Z-.5 F30 ; move away to clear the switch
M106/X P1 F30 ; move to positive limit wired into input #1
G91 X-.5 F30 ; move away to clear the switch
M105/Y P2 F30 ; move to negative limit wired into input #2
G91 Y.5 F30 ; move away to clear the switch
M26/X/Y/Z ; set home

;Enable all limits
M95 /101 /102 /103 /104





AFTER you edit the home program, the next time you start the wizard be sure to switch to "Custom User Defined" so the wizard will not overwrite your custom home program.

[Chaz]

So ironic. I use the same switches and same problem. At least I know how to sort now. Thanks.