vutek h2000 carriage height calibration

so i had the bottom limit sensor and mechanical limit setscrews come loose and carriage needs to be adjusted. due to covid we are not allowed to have a tech come out so im trying to do this myself. what i think is the mechanical limit shout be set first then bring the sensor down so it stops from the software before the mechanical limit. any direction would be fantastic so i can get this thing up and running again. i have got it currently where the mechanical stops it just a hair above the belt and the sensor stops it about .020" but i cant get it to calibrate the carriage gap correctly. it thinks it is .020 higher than it actually is.

 

The mechanical is very close to .030 judging by my .060 shim. ive got the sensor stopping it at exactly .060 when fully dropped. crazy thing is when i put material in like nitrile vinyl .080 thick i have to run a carriage gap of 0 to get it at a true.075 gap. if i put in thicker material like 1/4" i have to add carriage gap to get the desired .060. strange that its not raising the carriage proportionate to the material thickness. i print on thin sticker paper to 1" thick mats. unfortunately i change material frequently, but it is printing i just have to carefully adjust the carriage gap per material thickness.