Max height problem with printer

Ok, let me start out by saying I'm completely new to this. I have a ZD-One 3d printer. When I hit the about button on the interface screen it says MKS Robin_mini 2.0.7. I suppose to be able to print to a 250mm height. When I manually move the head it stops at what it says is 255. After measuring it is about half that. Opened the config file and adjusted to 500mm. Getting the same thing. Measuring from bed to end of extruder. Did a search couldn't find anything on it. Any Suggestions?
Attachment 12453

you need to zero the z axis.
depends on the firmware and slicer how you do it.

Usually it's through the control panel.
Is your z stop at the top or bottom of the machine ?

ie: what happens when you 'home all axis' ?

it is at the bottom. When home is hit , the build table pulls all the way back and the extruder almost touches the left front corner of the plate. The z switch is made when this happens. I have 2 3/4" from the plate to the tip of the extruder max up. Control panel shows z:255.00 at this point and z:0.00 at the home and bottom position. Conversion chart shows 255mm is 10.03 inches.

ok I got it.got a new config file from manufacturer. Works correctly, after I loaded . But, every time a turn off machine it reverts back to before. I have to reload config file every time. This doesn't seem right to me. Any suggestions