ask about demo in matlab

*hello every body Iam needed to do DC motor in the matlab /simulink,Iused dc motor that found in example Two Degree-of-Freedom PID Control for Set point Tracking in help/matlab .but the load torque in the under mask is carry postive signal,why does load torque carry postive signal?,and when put scope on the terminal Td did not appear the load iam needed the equations for this dc motor in this demo please help me thank you...............