Modbus RTU out of range

Hi everyone

I am trying to read some values out of a sensor connected to the PC over a RS485 serial adapter.

Currently I am trying to read the values with the modbus communication in matlab (MODBUS Communication - MATLAB & Simulink - MathWorks Schweiz). I am able to read the values in the first holdingregisters, but as soon as I go higher than 30, there's an error message telling me the address and count are out of range.

Smaller addresses are read correctly and I also checked that with a python script I am able to read the higher adresses. Did anyone have that same problem? Or does anyone know of a better library I could use? As I see it, the modbus communication I am using must have some limit on which addresses can be read...

Thanks, in advance!