Basic Plot with Units - Problem

Dear Friends,

I'm quite new in Mathcad. I have basic question: I'd like to plot a graph of sin() function. I'd like to have argument of time in seconds and return values in Volts. If I insert for X-axis (which is variable t) unit s, Mathcad automatically makes this axis unitless [(1/s) *s]. What am I doing wrong? I know that I cen generate vector o time samples t:=0s,1s..10s but I don't understand why can't I simply change units from unitless to seconds?

I attached picture.

Thank You very much in advance for help.

Best regards,

Wojciech