Wrong G81 Z retract

More
23 Aug 2011 14:05 #12677 by BigJohnT
Replied by BigJohnT on topic Re:Wrong G81 Z retract
Kenneth,

The only way I can replicate your findings is to press the pound key and switch to machine positions...

John

Please Log in or Create an account to join the conversation.

More
23 Aug 2011 15:28 - 23 Aug 2011 15:29 #12678 by piasdom
Replied by piasdom on topic Re:Wrong G81 Z retract
BigJohnT wrote:

Nope, runs fine on 2.5 too.

On the DRO tab do you have a leftover G92 offset that was not cleared by some other program that you ran?

John


this is at the beginning of all my files, so i'm guessing no ? :)
dro, all 0....g54 set

g17 g20 g40 g49 g54 g80 g90 g94 g92.1
Last edit: 23 Aug 2011 15:29 by piasdom.

Please Log in or Create an account to join the conversation.

More
23 Aug 2011 15:31 #12679 by piasdom
Replied by piasdom on topic Re:Wrong G81 Z retract
BigJohnT wrote:

Kenneth,

The only way I can replicate your findings is to press the pound key and switch to machine positions...

John


i tried changing views and it did make a difference. changed the preview path from
z-.75" to 0". in actual/relative now.

Please Log in or Create an account to join the conversation.

More
23 Aug 2011 15:32 #12680 by piasdom
Replied by piasdom on topic Re:Wrong G81 Z retract
ArcEye wrote:

and i seen epp somewhere and saw it today in the bios... set at bi-dir.. does this matter to emc or is this for printers ?


BIOS should set the parport as EPP for emc

Bi-directional is for older printers and devices to be able to report back ink levels, confirm ready for next data packet etc. as far as I am aware.
Was overtaken by IEEE 1284 ECP for most new printers.

Whilst EPP is bi-directional, there is a different protocol.

regards


Thanks ArcEye,
i'll change that as soon as i can.

Please Log in or Create an account to join the conversation.

More
23 Aug 2011 19:19 #12690 by andypugh
Replied by andypugh on topic Re:Wrong G81 Z retract
ArcEye wrote:

BIOS should set the parport as EPP for emc


I don't actually think it matters unless you are using the Mesa or Pico cards.

Certainly a problem there will have no bearing on the behaviour of the G-code interpreter

Please Log in or Create an account to join the conversation.

More
23 Aug 2011 19:45 #12691 by PCW
Replied by PCW on topic Re:Wrong G81 Z retract
I think theres a subtle difference with some PP cards where
EPP mode makes some pins that are open drain+pullup in SPP or bidirectional mode
change into push-pull mode, but not relevant unless you are trying to source current from a
parallel port pin

Please Log in or Create an account to join the conversation.

More
23 Aug 2011 20:17 #12692 by andypugh
Replied by andypugh on topic Re:Wrong G81 Z retract
OK, here is what I think is happening.

When you issue a canned-cycle command, the retract plane and clearance plane are stored, and remain the same until you issue a G80 (cancel canned cycle) or perform a non-canned cycle move.

So, if you are in G98 and issue a G81, the current Z is stored, and the R from the G81 command is also stored.

If you do not issue a G80 then the next G81 retracts to the first-stored Z, regardless of where the axis was when the second G81 was issued.

It is possible (but untested) that a % at the start and/or end resets out of canned-cycle mode.

For safety, any G-code using canned-cycles should begin and end with a G80.

The advantage of this behaviour is that you can drill a series of holes like this:

G0 Z3
G98
G81 R 0.1 Z-1 X0 Y0
G81 X1 Y0
G81 X0 Y1
G81 X1 Y1 (and so on)

Please Log in or Create an account to join the conversation.

More
23 Aug 2011 22:13 #12697 by piasdom
Replied by piasdom on topic Re:Wrong G81 Z retract
Thanks andy, but at the start of ALL my file i have - - g17 g20 g40 g49 g54 g80 g90 g94 g92.1
and if i use a canned cycle, i use the cancel when done with it. as in the file, i use g81 til the end and then
use g80. it should stay g81 thru the whole file as that is all i'm doing in this program.


Thanks all for the help !
kenneth

Please Log in or Create an account to join the conversation.

More
24 Aug 2011 09:46 - 24 Aug 2011 09:57 #12712 by piasdom
Replied by piasdom on topic Re:Wrong G81 Z retract
and if i use the below, z would retract to 3". as it ignores g81s' r.
move to the last position of z(xy to i guess) before g89.
i have to center drill inside a pocket. so i have to put g0z.....g98.....g81
wherever i want to change the retract height ?


The advantage of this behavior is that you can drill a series of holes like this:

G0 Z3
G98
G81 R 0.1 Z-1 X0 Y0
G81 X1 Y0
G81 X0 Y1
G81 X1 Y1 (and so on)

change retract by;
g80
x1 y0
G0 Z-.7
G98
G81 R -.75 Z-1 X1 Y0 (will not use r-.75)
X2
X3
Y4 (and so on)
Last edit: 24 Aug 2011 09:57 by piasdom.

Please Log in or Create an account to join the conversation.

More
24 Aug 2011 11:35 - 24 Aug 2011 11:50 #12713 by piasdom
Replied by piasdom on topic Re:Wrong G81 Z retract
if i start with the below(no g98 g99), the file runs as it should but the plot path is different.
the plot shows the path as going .08 for both top and bottom.
changing views have no effect for me.


g17 g20 g40 g49 g54 g80 g90 g94 g92.1
(C-Drilling)
m6 t5
g0 z.1

g81 f8 x.225 y-.125 r.08 z-.02 retracts to .08
.....
.....
......
x1.119 y-.77 r-.775 z-.96 retracts to -.775 - - plot shows .08

Thanks
kenneth

edited;
i restarted emc(messing with xml) and now the tool follows the plot path. all
holes retract to .1
Last edit: 24 Aug 2011 11:50 by piasdom.

Please Log in or Create an account to join the conversation.

Time to create page: 0.135 seconds
Powered by Kunena Forum