How to Prevent Different Grain Commodities from Mixing in Shared Equipment Paths

[leonize_meiring]

Problem statement

I am modelling grain receiving and dispatching in FlexSim and need to prevent commodity mixing across shared equipment.

A truck can either unload grain into the system or load grain from the system. Each truck has:

• A commodity label (Commodity / Load_Commod)

• A tonnage label (Load_Ton)

The tonnage logic is working reasonably well, but I am struggling with the commodity control logic.

The challenge is that commodities cannot mix anywhere within the material handling route. The restriction is not only on the conveyor itself, but on the entire material handling path.

For unloading, the route is:

Truck → Hopper → Conveyor → Elevator → Conveyor → Bin

For loading, the route is:

Bin → Conveyor → Elevator → Temporary Bin → Truck

The issue occurs when consecutive trucks have different commodities and need to use the same equipment route.

Example:

• Truck 1 unloads Commodity 1 through Hopper 1

• Truck 2 unloads Commodity 2 immediately afterwards and also requires Hopper 1

Truck 2 should not be allowed to enter until:

1. Hopper 1 is empty

2. The downstream conveyors are empty

3. The elevator is empty

4. Grain has reached the destination bin

5. No residual Commodity 1 remains anywhere in the route

Currently, Commodity 2 can enter while Commodity 1 is still somewhere in the material handling chain, causing grain mixing.

Requirement

I need a scalable, standard FlexSim solution (minimal custom code) that:

• Prevents commodity mixing across an entire equipment route

• Allows only one commodity per route at a time

• Automatically releases the route once all associated equipment becomes empty

• Works when adding additional bins/hoppers later without rewriting code

• Integrates with the existing truck labels (Commodty, Ton)

My question is whether the correct approach is to lock an entire equipment route using a route commodity state/label, or whether there is a more standard FlexSim method to achieve this.