I made a router (x) 2500mm (Y)1200mm (Z) 350mm .Control board XHC Ethernet 3/4/6 Axis MACH3 CNC Motion Control Card Frequency 2000KHZ , motors CNC DSP Stepper servo drive 8A 30~100VDC Matching 86mm NEMA34 motor HBS86H Leadshine (VALLDER). 4 engines x,y,z,(and slaves).
PROBLEM

Calibration passed great for all axis except for (y). I calibrate for example 1200mm works great. MDI 1200mm works great BUT if I do MDI 500 MM ERROR 0.8 MM. BUT I ADD ANOTHER 700MM IT FINISHES EXACTLY AT 1200MM. KNOW EVERYTHING BETWEEN 0 AND 1200 MM IS error

Thank you very much in advance


P.S
I changed control boards, motor, mechanics, drivers, etc

as if it works with degrees and not mm

Did you calculate the steps per using the screw pitch and steps per rev of the motor and any gearing or did you use 1200mm distance and the wizard?