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Re: home sequence
« Reply #20 on: March 11, 2012, 11:25:43 PM »
Nice work guys !
The intermediate programmed point is in Program coords, then shifts to the absolute for the G28 home pos., gotcha.
Another wrong assumption on my part, after a single axis int. move I expected BOTH axis to go HOME.  gotcha.
Much better now, thanks.
Russ

I agree with you, Rich on the word play. One can get confused.
This is the grip I have on it. 
 
I've come to know Referencing an axis and Homing and axis as one in the same.
The Referenced position and Home position can however be different positions in the same Machine coord system.
Go to Home (G28) should not be confused with the act of Homing. (other than it traverses to the Home pos.)
Go to Machine Home (G30) should not be confused with Referencing. (other than that it traverses to the Ref pos.)

Offline RICH

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Re: home sequence
« Reply #21 on: March 11, 2012, 11:36:39 PM »
Terry,
Never used the G30 so just added some info on it from what I could find.
I would think that the majority of folks will never have need for it.
Have any other insight into Mach's definition and use?

So what's the best descriptive words if one dosen't use switches or soft limits?

RICH  
Re: home sequence
« Reply #22 on: March 11, 2012, 11:45:02 PM »


So what's the best descriptive words if one dosen't use switches or soft limits?

RICH  


Here I go assuming again  ;D
I would jog the axis's to there extremes, just shy of crashing and mark the slides as mentioned in the manual. Set this as the REF pos.
Then set the SL accordingly anyway (just to protect the mach) and the G28 pos where ever you wish.
You have to of course locate the fixture/part as usual.
Just sumin',  ;) Thanks,
Russ :)

Offline RICH

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Re: home sequence
« Reply #23 on: March 11, 2012, 11:45:47 PM »
Hey Russ,
The word play is a killer for sure and Smid dosen't even talk about homing but rather always refers to machine zero.
Then things get a little more complicated when you consider the implications of not having switches or whatever.
And just think, all we wanted to do is go home and have a nap! :D

RICH

Offline RICH

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Re: home sequence
« Reply #24 on: March 11, 2012, 11:55:56 PM »
Russ,
No wonder I make machine=part=program and the code is all based on the end and center of the lathe stock equal
to zero also.
Of course that only works for  simple operations.  ;)
RICH
Re: home sequence
« Reply #25 on: March 12, 2012, 07:22:42 AM »
Thanks for the assistance Rich, I guess G28 is fine and I was reading something into the somewhat vague description that wasn't really there.
I set the motor tuning way slow on a sim pc to clearly see the effects and have a pretty good grip on it now.

.... and there's the Home Off values (if used), yet another position.

G28 would be good to use as a TCP or Matl. load pos. Very quick and easy to add a button to the screen too.

Dear Fred, THANKS for the post ... and, sorry for the ramble.

Thanks Rich,
Russ
« Last Edit: March 12, 2012, 07:28:39 AM by Overloaded »

Offline BR549

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Re: home sequence
« Reply #26 on: March 12, 2012, 11:54:26 AM »
Do you want the short or long story(;-) ???

(;-) TP

Offline RICH

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Re: home sequence
« Reply #27 on: March 12, 2012, 12:03:57 PM »
Do you want the short or long story
Whatever one you pick Terry would be fine with me, but the long story sounds more interesting.....  :D
RICH

Offline BR549

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Re: home sequence
« Reply #28 on: March 12, 2012, 01:04:37 PM »
OK with Mach3 ,

Machine Home (zero)
 Can be set by switches,
OR REhome Button if you have no switches,
OR is set by mach when you OPEN it to the current position
OR can be zeroed to a postion via CB
OR rumored to be settable via #vars 5161-5166 (untested as yet)

Moves to get to machine home,

G53 X0 Y0 Z0 ------- Makes a straight traverse run to Machine Zero

With G30 ALL axis go home
G30 --------------------- Makes a straight traverse move to machine zero
G30 Z0 ------------------Makes a single Z move to Zero THEN all AXIS make a straight traverse move to Machine zero
G30 Z0 X0--------------Makes a Straight traverse move to Z0 X0 then all axis makes a straight traverse move to machine zero
ETC,ETC

Local Home(G28), Is an offset from Machine ZERO.  With G28 without defined axis all axis goes home in the order of Z then all the rest. USED with a defined axis ONLY the defined axis goes home via the intermediate point.

It can be the same as Machine zero or different as defined

Moves to get to Local Home

G28 ----------------- Raises Z first then makes straight traverse moves in XY to Local Home(LH)
G28 Z-1 ------------ Single axis move to intermediate point(-1.000) and then goes to Z0. Z axis ONLY goes to LH
G28 Z0 X0 --------  ONLY the defined AXIS will go to LH UNDEFINED axis remain as is . Makes a straight traverse move in ZX to 0 then ZXmoves in a   straight traverse move to LH.
ETC,ETC

Part HOME ( Part Origin, X0Y0 Z0)

G0 Z0 X0Y0 ----------------- Makes a straight traverse RAPID move to Z0 X0Y0
G1 Z0 X0 Y0 ---------------- Makes a straight traverse FEERATE move to Z0 X0 Y0

Fixture Home  

G55 G0 Z0 X0 Y0  -------- Swithes the Fixture offset then goes to X0 Y0 Z0 as straight traverse move at rapid speed
G56 G1 Z0 X0 Y0 F100 --------- Swithes the fixture offset then goes to X0 Y0 Z0 as straight traverse move at feedrate speed



*************************************************

You will note that the G28/30 in MACH3 is backwards to FANUC . In the fanuc world the G30 local Homes can be set in the parameters AND there can be MANY etc;  G30 G30.1 G30.2 G30.3 etc,etc

Also the Axis calls in G28/30 are different from each other. In g28 you can call a single axis to home, in G30 ALL axis go home reguardless

Just a thought, (;-)TP
« Last Edit: March 12, 2012, 01:06:56 PM by BR549 »

Offline RICH

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Re: home sequence
« Reply #29 on: March 12, 2012, 06:53:47 PM »
Thanks Terry as the post is additive.
RICH