Fanuc 16i mb work offset setting issue 3 axis VMC

Hello Guys again,

after months of problems, with the help of this forum, service engineers, mtb and so on , I am getting hopefully close to have my 3 axis VMC running again.

Basically now the machine is let's say working , but I am having an issue setting work offsets.
I did look at other threads but I couldn't see one which describes the same problem.

I try to explain this as good as I can , so:

Basically I lost all parameters , so I had to re load everything( all parameters except PMC were the ones I transfered via RS232 prior to memmory all clear) , that seems like it worked.

Now, I have been using the same method to set work offset on x and y on Fanuc for 18 years , which is basically find what ever point then go on G54/G55 and type x0, measure(soft key) , y0 measure(soft key) , but when I look at the absolute position screen , it shows instead of x0 and y0 , it shows for instance something like x-0.04mm y+0.005mm , also when I press reset it does strange things like it resets the z datum to the absolute position set on g54/g55 work offsets.

I don't understand what is going on , I might try to record a little video as I find difficult to explain otherwise.

Just another detail I noticed doing this ( it might have been like that before I am not sure) , once I reset , if I was on g90 for instance , once I press reset button g91 becomes modal.

Many thanks in advance.

Sounds like your backup parameters did not match how the machine used to run. You need to start reading the parameter manual at parameter 3100 through about 3450. Lots of those will not apply or need to be understood so you can skim them. Look for the ones that control what happens to the coordinate system and program codes when at power on or clear or rest conditions. For example 3402 bit 3 and bit 6 will affect the switching of G90 to G91 when reset is pressed.

I will surely do that!

Hello there

I did check the parameters but I couldn't find the ones which will sort my problem out of the problem is parameter related.

I just double checked and at the moment when I press reset , machine reset the z value to a certain value all the time , no matter where the machine is on the z travel.

Regarding x an y, when I go in position in g54 g55 and so on , when I re clock for instance the hole , and I do the X0 measure, y0 measure the values on what ever offset I am setting to , do change , but then if I press reset then , and I look at the absolute values of x and y in the position screen , I see( I believe ) the difference of the amount I moved the datum on x and y.

Does this explain the problem better?

Does your control have a Man/Abs switch?

poxino said:

do you mean this?View attachment 285628

Click to expand...

Yes. That needs to be in ABS. Not sure how it's set or how you change it on that control, but if it's in MAN, it can cause weird behavior like you describe.

Basically, it resets the absolute position to the current position when you hit reset and go into manual mode. It's a clunky way of shifting the zeros on the fly, and mostly just confuses people.

guest said:

It's a clunky way of shifting the zeros on the fly, and mostly just confuses people.

Click to expand...

I'll agree with that

Correct, that's basically what the machine is doing in very short words.