Flows

Flows are a type of building block for the Map and Model layers.

The job of flows is to fill and drain accumulations. The unfilled arrow head on the flow pipe indicates the direction of positive flow.

The default flow type is the uniflow, which flows in one direction only. You can also use a biflow (bi-directional flow).

To place a flow on the diagram

1. On the Map or Model layer toolbar, click the flow tool.
2. The uniflow is the default flow type. To place a biflow in your model, click and hold the flow tool on the toolbar and then select the biflow from the list that appears.
3. Move the mouse pointer to the location where you want the flow to start on the diagram.
4. Click and drag to the place where you want the flow to end.
5. Release the mouse button to place the flow.

6. To edit the properties of the flow, select the flow, and then select the panel for the properties you want to edit.

   Tip: Double-click the flow icon to automatically select the default field for the entity on the currently displayed panel.

   For more information about placing, naming, and editing flows, see Working with building blocks.

To bend a flow pipe

While you click and drag to place the flow, press the SHIFT key and move the mouse pointer in the direction of the bend each time you want to insert a bend. Each time you press the SHIFT key while you continue to click and drag, a 90-degree bend will be put in the flow pipe.

To draw an outflow from a stock

Select the flow tool, and start the click-and-drag with the mouse pointer inside of the stock. If the pointer is not within the boundary of the stock when you begin dragging, the flow will be drawn with a cloud at its source.

To draw an inflow to a stock

As you drag the flow, make sure that the mouse pointer makes contact with the stock before you release the mouse button. The stock becomes highlighted on contact to let you know that the connection has been made and that you can release the mouse button. If you release the mouse button before the connection is made, a cloud appears at the destination end of the flow pipe.

To replace a cloud with a stock

Select the stock with the Arrow tool, then drag the stock over the cloud. When the stock is over the cloud, the cloud becomes highlighted. Release the mouse button. The flow is now connected to the stock and the cloud disappears.

To disconnect a stock from a flow

Select the flow with the Arrow tool, then click the move handle at the end of the flow that is connected to the stock and drag the handle away from the stock.

To move a cloud

Click and drag the cloud to the new location. The flow will remain attached.

To change the direction of a flow

CTRL+click (Windows) or COMMAND+click (Macintosh) the flow arrowhead. The arrowhead moves to the opposite end of the flow.

To display polarity for a flow

Polarity is used to visually indicate the cause-and-effect relationship between two model entities.

For flows, the polarity is determined by the flow's association to the attached stocks: an inflow always has a positive (+/s) influence on a stock and an outflow always has a negative (-/o) influence on a stock.

• Right-click the circle portion of the flow icon, choose Polarity from the menu that appears, and then choose +/s, -/o, or None.

For more information about polarity, see Assigning polarity to building blocks.

To create leakage flows for conveyors

Second or subsequent outlfows for conveyors are automatically defined as leakage flows. Use the following procedure to add and define a leakage flow for a conveyor.

1. Add a second (or subsequent) outflow to the conveyor.
2. Select the second (or subsequent) flow.
3. Click the Equation panel.
4. In the "Options" section, use the Leakage, Leak integers, and Leak zone options to define the leakage represented by the flow. For information about each of these options, see Flow options.
5. In the "Parameters" section, specify the leakage fraction. For more information, see Flow parameters.

To define queue outflows

• A queue can have multiple, uniflow outflows.
• A queue's outflows are constrained only when there in an oven or an inflow-limited and/or capacity-constrained conveyor immediately downstream of the queue.
• Unit conversion is possible in flows that connect queues to other stocks. For more information, see the discussion of the Unit conversion check box in Equation panel.
• When a queue has multiple outflows, you can designate one or more of the outflows as an "overflow". When a higher priority flow is blocked because of capacity constraints, the flow will be routed through the overflow. For more information, see the discussion of the Overflow check box in Equation panel.

To define oven outflows

• An oven can have a single, uniflow outflow.
• An oven's cook time is specified in the oven's parameters. When the oven's cook time has expired, the oven will spit out its entire contents in an instant. At all other times, the oven's outflow will be zero.
• Unit conversion is possible for oven outflows. For more information, see the discussion of the Unit conversion check box in Equation panel

See Also