DOBOT MG400'I/O => 24V-18V? Need 24V-0V,Help

[Denryo]

I checked DOBOT MG400’s I/O voltage using tester.
tester shows that I/O ON -> 24V, but I/O OFF -> 18V!
I need 0V, because another device cannot work 24V-18V,

Does anyone have the same Trouble?
Please contact me and let’s solve this problem or please tell me how to solve.

thanks

[hans99]

This is the robot IO generated virtual voltage, this situation, 18V does not have any driving ability

[fuzzy_l]

“-” electrical circuits connected?