Question....... Over the years working on Fanuc controls I always wondered why the Fanuc control will use the Relative display value and add it to the tool length offset when measuring tools? on other controls it will not do this and only use the machine coordinate system for offset values. what parameter can be changed to fix this????

Good morning, I have worked on many control types in my years of programming, so I am not a novice. I have over thirty years of CNC programming, process development, working with manufacturing cells, and I teach Machine technology at a local trade school. I have worked with Haas, Yasnac, Meldas, Mazak, Fanuc to name a few over the years. The Haas and Yasnac are my favorites, very user friendly and logical. I feel that I am just not seeing something in the Fanuc control in regards to tool length measurement and setting at the machine, and hoping some one can shed some light on the matter for me... My method for tool length offset at the machine (dynamic measurement) is as follows: 1) I measure off the machine table on top of a 1-2-3 block, the 3" side. 2) Set all the tools at this point, enter the lengths into the height offset registers. 3) I them measure from the top of the measurement block to the top of each of my work piece Z-zero planes and set my work offsets as required, G54 vise one, G55 vise two and so on... 4) If I need to change a tool it is always measured on top of the block as listed above. Easy method, fast accurate and no fuss to get a job running. On the Haas, and other controls I just enter the length coordinate of the machine "Z-axis" directly into the length offset register and it is done. My question is this; I notice on a Fanuc control, it will add what ever active work offset G54-G59 Z values to the tool length when you write it into the register Why Why why?? and how to get it to stop doing this??? This has frustrated me for years, I wonder if any one knows how to make it read only from the machine coordinate system. The Haas control has two parameter settings for tool length offset, Fanuc, and Haas when set to Fanuc it does exactly as described above. I tell every one who has a Haas to turn the Fanuc style off.... Over the last several years I have worked on Okuma and Haas machines so it has been a while since I worked on a Fanuc.