Using Manipulate[ ] with physical units

Question

I'm a new user, and am trying to build a simple Boyle's law system in Mathematica. I want to include the units of the values, as I may need to perform some conversions later. If my quantities are a discrete list, they work fine. I cannot seem to get it to work for a slider. Can you help? I need this for work, and it's quite urgent. I've searched for a while before posting this question. Here's my code:

Manipulate[
 Text@Style[
   Grid[{
     {Row[{"Total fill volume is ", totalVolume}]},
     {Row[{"Delivery rate is ", deliveryRate}]},
     {Row[{"Product duration is ", 
        duration[totalVolume, deliveryRate]}]},
     {Row[{}]},
     {Row[{"Initial pressure is ", initialPressureG}]},
     {Row[{"Drop in pressure is ", pressureDrop, "%"}]}
     }, Alignment -> Left]
   ]
 ,
 {{totalVolume, Quantity[30, "ml"], "Total fill volume"}, 
  Quantity[{30, 45, 60, 90}, "ml"]},
 {{deliveryRate, Quantity[1, "ml/day"], "Delivery rate"}, 
  Quantity[{0.5, 1, 2, 3}, "ml/day"]},
 {initialPressureG, 0, 100},
 {{pressureDrop, 40, "Pressure drop"}, 0, 100, 5}
 ]

Instead of initialPressureG being a slider from 0 to 100, I want it to be a slider from 0psi to 100psi. Am I doing something stupidly wrong?

Answer 1

dur = Times; 
Manipulate[
 Text@Style[
   Grid[{{Row[{"Total fill volume is ", totalVolume}]}, 
         {Row[{"Delivery rate is ", deliveryRate}]}, 
         {Row[{"Product duration is ", dur[totalVolume, deliveryRate]}]}, 
         {Row[{}]}, {Row[{"Initial pressure is ", initialPressureG}]}, 
         {Row[{"Drop in pressure is ", pressureDrop, "%"}]}}, Alignment -> Left]],
   {{totalVolume, Quantity[30, "ml"], "Total fill volume"}, Quantity[{30, 45, 60, 90}, "ml"]}, 
   {{deliveryRate, Quantity[1, "ml/day"], "Delivery rate"}, Quantity[{0.5, 1, 2, 3}, "ml/day"]}, 
   {initialPressureG, Quantity[Range[0, 100, .01], "psi"], ControlType -> Manipulator}, 
   {{pressureDrop, 40, "Pressure drop"}, 0, 100, 5}]

Note: Use your function duration instead of dur.