[jai]

below is my expression:
0.5 [kg s^-1]*step (1-t/1[s])*step (t/1[s]-2)

from 0 to 1 sec mass flow rate is 0.5kg/s and then 1-2sec mass flow rate is 0kg/s and then it is 0.5kg/s

i want to create expression for this condition:
0-1 sec = 0.5kg/s
1-2 sec = 0kg/s
2-3sec = 0.5kg/s
and so on....