Initializing and Replenishing Supply Tanks

A supply tank is an originating tank that is a source of raw material for one or more downstream tanks. Often, supply tanks contain ingredients that feed into a mixing tank or hold chemicals that feed into a reactor. Typically, you replenish a supply tank when it gets low and make it available for use whenever it has an adequate supply. If you always stock the supply tank and it is always available for use, you do NOT need to model it since it poses no constraint on the process. You may set supply tanks to an initial level at the start of the simulation in the initialization logic, then use them as needed by a mixing or other downstream tank. To initialize the level in a supply tank, enter the following statement in the initialization logic:

Initialize tank level

Tank_SetLevel (<supply tank>, <qty>)

If, for example, you wanted to begin the simulation with the supply tank, WaterTank, filled with 800 gallons of water, you would enter:

Start with full tank

Tank_SetLevel (WaterTank, 800)

To gradually fill or refill a supply tank whenever it drops below a trigger level, use the Tank_Fill subroutine with a large fill quantity and an appropriate resume level. For example, the following statement will continue pumping up to 999999 units into TankA at a rate of 200 units per minute. Whenever the tank becomes full, it must drop to 400 units before filling resumes.

Resume fill with trigger level

Tank_Fill (TankA, 999999, 200, 400)