Having trouble with touch off

Hello Folks:

I am having trouble with the Touch Off function on my mill, I must be doing something wrong. The following is the procedure I am using.
I am using a vise which is mounted on the table and my Z axis 0 would be about 3 inches above the table.
Procedure
I load program that I want to use,
Open it up, axis displays the tool path, the programs run flawlessly when cutting air.
Home X, Y, Z.
Then I perform the touch off function, I use a feeler gauge., I set the offsets in the appropriate box and push OK.
I use G54 for my coordinate, I have also inserted G54 into the preamble of my program.
This is where it gets troublesome,
When I push the run function,
The Z axis moves down and settles out below the bottom of the work, also the X and Y, zero positions do not go to the Touch Off positions.
Obviously there is something I am missing, in the initial setup of EMC2 is there something I should have done and did't.
Am I doing the Touch Off correctly.
Any thoughts would be greatly appreciated.

The latest (2.5) version has options in the touchoff window to select the coord system
(G54, G55, etc.) that will be set. If your program has any G10 L2 Px commands in
it, it will change the coord system and nullify your touchoff setting. And, of course, if
you use G41, G42 or G43 commands, that will offset from the coordinate system
by tool radius or length settings.

I'm wondering why you home after loading the program, I always home when I
start LinuxCNC.

Jon

Thanks you Folks for getting back to me.

Here is the first few lines of the code as it comes from my CAM program. I have not modified it in any way.
%
G20 G40 G49 M6 T1
G17
M7
G0Z0.7874
G0X0.0000Y0.0000S7000M3
G0X-0.0938Y0.5159Z0.2362
G1Z-0.0625F0.5
G1Y1.0309F3.0
G2X0.0000Y1.1247I0.0938J0.0000
G1X0.7976
G1X0.8354
G1X0.8420Y1.1247
G1X0.8491Y1.1247
G1X0.8565Y1.1247
G1X0.8643Y1.1248
G1X0.8725Y1.1250
G1X0.8809Y1.1252
G1X0.8895Y1.1255

ps When I start up the CNC program it always diverts back to the splash screen showing the carving of the old Logo. Is this normal or have I failed to do something on the original installation?

Thanks for getting back to me.

In answer to your question, I just thought that that was the way it was done. The reason I thought that was every time I start up LinuxCNC I get the splash screen showing the carving of the original Logo. I thought it would be better if the splash screen showed my project while I was touching off.

Hello Folks

Thanks for the comments,

I will try them out next week and get back to you. My wife and I are off camping this weekend and I won't get a chance to play around with the mill until next Tuesday.

Chipmunk

Hello Folks:

I started from scratch and reset up my mill using the comments and suggestions from you people. Needless to say, I found and corrected a number of problems.

First of all I determined what my limits and travel is for each of the axis's and set the limits accordingly in the configuration for my mill. I decided that the bottom left hand corner will be my zero for the X and Y limits and the top of the column will be the 0 for the Z limit. The X travel is 0 to 11.625, the Y travel is 0 to 4.875 and the Z travel is 0 to -5.75. I then jogged all of the axis's to some value that moved them off of the home position and invoked G53 G0 X0 Y0 Z0 , the mill responded correctly.

I then set my G54 tool off set using a 0.0015 feeler gauge. Using the left hand side of the work I set the X offset to -0.0015 the Y offset was set at the bottom of the left hand side to -0.0015 and the Z offset was set to +0.0015 off of the to of the work piece. I then invoked G53 again and all off the axi's went to the home position.

I then edited the program and added G54 to the preamble.

The next move was open up the work program and home all of the axis's , they were already at zero because of the previous G53 command. I started the program and was immediately met with a error message, (Program Exceeds Maximum on the Z Axis) I pushed run anyway,

I then was greeted with another error message (Linear move on line 5 would exceed joint's positive limit.)

That is where I am at now, attached is the the first 24 lines of my Cut 2 D program.

%
G20 G40 G49 G54 M6 T1
G17
M7
G0Z0 0.7874
G0X0.0000Y0.0000S7000M3
G0X-0.0938Y0.5159Z0.2362
G1Z-0.0625F0.5
G1Y1.0309F3.0
G2X0.0000Y1.1247I0.0938J0.0000
G1X0.7976
G1X0.8354
G1X0.8420Y1.1247
G1X0.8491Y1.1247
G1X0.8565Y1.1247
G1X0.8643Y1.1248
G1X0.8725Y1.1250
G1X0.8809Y1.1252
G1X0.8895Y1.1255
G1X0.8983Y1.1259
G1X0.9073Y1.1264
G1X0.9163Y1.1271
G1X0.9253Y1.1278
G1X0.9342Y1.1288
G1X0.9430Y1.1298
G1X0.9516Y1.1310
G1X0.9600Y1.1324
G1X0.9680Y1.1339
G1X0.9756Y1.1355

Could you please have a look at this and advise me as to what to do.

Thanks Chipmunk