axis problems

[desutt]

I am trying to learn how to use my new machine.  I am having a great deal of difficulty getting any repeatability in the movement of axis'.  I have set my homing position to z=0, y=23, z=3/6 on a 24 x 24 inch by 3. 6 inch platform and saved the configuration.  If I home my machine and close mach 3 and then reopen it my DRO's do not reflect the home position that I left the machine in.  I have done nothing other than close mach3 mill.  When I reopen mach3 mill my DRO's read all zero. It seems to me that they should show the home position since I have done nothing except close and reopen mach3 mill.  What am I missing?  Another problem I have is that when I insert a g20 into my program the measure unit go haywire.  In a simple program that works fine the first two lines are;
g0 f80
g1 z2 x8.5 y16
This program works fine.  If I make the first line
g0 f80 g20
the the x and y axis movement (per the DRO's) is scaled by ~1/28 and the z by ~ 1/22.  I have changed nothing except to edit the g code in Mach3 saved it and regenerated the tool path.

Image 1 is the DRO's prior to adding the g20, image 2 is the DRO's after the g20 is inserted and the x and y axis are manually moved (tab) 1 inch and the z axis 3.5 inches.

Any Help will be appreciated.

[ostie01]

Your homing position should always be 0.000 in Z, Y and Z

Go to General confing and check persistent DRO (I think)

Jeff

[desutt]

I checked persistent DRO, did not help.  Thanks anyway

[Hood]

Config, General Config, Lower Right corner you will see Copy G54 from G59.253 on Startup, make sure that is unchecked.
For your other problem can you attach your xml and I will have a look.

Hood

[desutt]

Ok thanks for the help.  Is anyone having a problem with G20/G21 operating backwards.  I have my machine set up in inches, but when I load a program that contains a G20 it my coordinates swithc to mm, if I replace the G20 with a G21 it goes back to inches.

[ostie01]

Did you close Mach3 after setting unit, you must


Jeff

[desutt]

I can't find where to set the unit.  Must have set to inches when I got it.

[ostie01]

Go to Menu config and the first item is Select Native Unit


Don't forget to close Mach and re start

Jeff

[desutt]

This is for setting up motor tuning not units for g code.  I am afraid to change this as I fear screwing up the motor steps.

[ostie01]

I don't know if I understand your question or you want to do something else but look at the image.