Tool offsets, auto tool change with auto probe

JPoepsel

Hey all,

I know, I'm not the first asking, but since I did not find a staisfying answer, I ask again ;-)

The current status of my CNC machine enables me to do automatic tool changes by using a homebrew T.nc. I control the valves of the ATC by an ESP8266 connected to the DDCSV by its serial interface. This works fine and alows me to use up to 32 extra inputs and outputs. If anybody is interested in this solution, please write me a  PN.

Now the next step is to do an automatic tool height mesurement and compensation. My plan is to write a G code, which takes every tool in the holder, measures its offset and stores it in the controler. I assumed, that the tool offset paramers #267... would help me, but they seem not to work, as expected. Changing their values does not change anything!
E.G.: Setting #267 to 0 and #268 to 50 and than executing th G code

M3
M6 T1
G90 G1 x100 y0 z0 F1000 S8000
G90 G1 x0 y0 z0 F1000 S8000
M6 T2
G90 G1 x100 y0 z0 F1000 S8000
G90 G1 x0 y0 z0 F1000 S8000
M5
M2

results in exactly the same z Position of the spindle for tool 1 and tool 2.

I assume I can handle this by changing the T.nc macro and correcting the Z coordinate offset there by using #267...
But: If I do an automatic probe, how can I write the results automaticely to this values? Simply setting them to a value in the G-code does not work. Inspecting them after a change by G code in the paramter page shows them unchanged.

All in all this more General questions result:
- Are there any internal variables #xxx, which can be changed by G-code and which remain unchanged after a program ends and even after power down?
- Is there a general rule, which #xxx values can be overwritten by the user? (Are ther any #xxx variables, which are read only, write only and read+write?)
- What's about the newly introduced #2000++ Parameters. They are free to the user, but can they be changed in G code or can the only be read there?

Can anybody help me?

Josef

JPoepsel

Hi again!

So, if nobody talks to me, I have to talk to myselve...

I was wrong when saying that it is not possible to write the tool offsets by G-code.
The trick is, that the tool offsets #268... are mapped to the G code variables #768...
I detected this 500 difference some month ago and simply forgot it.
So:
G0 Z#768; will move the spindel to the height of the first tool offset
and
#768=123; will set the first tool offset to 123, which can be checked by looking into the parameter page

The general question: for which parameters do I need to add 500 when mapping the parameter# of the parameter page to a G code variable?
(I guess for all parameters of the page <500, in contrast the #2000++ parameters seem to have identical numers in G code)

Oh, it would be so nice if someone with real knowledge would share it with me. My CNC is in my garage 70m away, my PC in the house and it is cold outside! And having a walk of 2x70m for every line of code I change is a bit  anoying...
(Yes, I know that I can connect a keyboard to the DDCSV, but there is no heater in the garage so I prefer Walking to the warm house again and again...)

So more questions...
E.G.
- What are the G-Code variables #448 and  #420..423 for (e.g. used in G153 code)
- Is it correct that the "MACH" coordinates and the G53 coordinates are offseted by # 800- # 803 (X, Y, Z, A) and that I can change this offsets not by the keypad but only by G-code?
- What does the probe functions M101 and M102 realy do and what is the exacto meaning of #400...
- If tool Offsets should work independently from the choosen coordinate System (G54,55,...), what variable should I use to correct the Z Zero Position? #802?

So many questions. May be I find out by myselve after some hundred meters walk...

Josef

oliver

sorry the topic is dead