On Apr 6, 3:16 am, r norman <r_s_nor... from comcast.net> wrote: > Vcmd = I Rs + Vm -- you have this correct. > > Now just write Vm = Vcmd - I Rs. And as I = Vm/Rm + C dVm/dt, then Vm = Vcmd - (Vm/Rm + C dVm/dt) * Rs.