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?

steps per mm not correct. But don't ask me, how to change on this printer.

post your config file, people miss interpret how to read this file..

Also one broken line and it stop loading the config...

...Or the jumpers are not correct for the Z driver. If the control board is using a RAMPS or clone, then the jumpers to set micro-stepping might be wrong for the firmware. I googled the printer, and I found it, but I can't see the control electronics.

Edit: I see that it has a touchscreen, which implies that it's not Marlin firmware. It may not include source.

Edited 1 time(s). Last edit at 01/17/2019 12:49PM by SupraGuy.

---

MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

@SupraGuy

No its not marlin, but it is still all configured by a config file.

Don't know anything about these machines but i guess we all start from the basics.
Home the z axis and check its zero.
Concern will then be that the Z axis calibration is correct. Its supposed to be correct out the box.
Might need to be clear on what the config file does. Might be called that on the screen but may not be the firmware configuration.

Don't know how it drives the z axis but check there is nothing loose. Most of us will probably assume 2 z motors which would tend to go wonky but it could be one with a belt.

For info:-
The firmware usually has a max value limit set to stop the printer being damaged if you input incompatable values. In this case yours seems to be set to 255 = perfectly reasonable since they say it should be ok to 250mm.
There is no position feedback on these printers = they don't know where they are physicaly. You home the axees till they activate a prepositioned switch/sensor. This is then defined as Zero (assuming switches at minimum) the distance is then calculated based on the number of electronic pulses sent to the motors. The number of pulses per mm is a number set in the firmware by the config file. Calculating this number is part of the calibration proceedure needed for self builders. As a purchased kit yours should be pre installed correctly.