On a Context diagram, Input, Control, or Mechanism ICOM Arrows are drawn from space into the single Operational Activity symbol on the diagram. Output ICOM Arrows are drawn from the Operational Activity symbol into space. The same ICOM Arrow tool is used to draw all four types of lines:
1 In an open OV-5 Activity Model diagram, select the ICOM Arrow tool on the Draw toolbar.
2 Draw the arrow from blank space to the side of the Operational Activity symbol into which you want the arrow to go, following the ICOM Arrow rules of placement.
3 Name the ICOM arrow and click OK.
The Associative Properties dialog appears. To tunnel the arrow, check the appropriate Tunneled (Parentheses) check box and click OK.
When an arrow into a box is tunneled, it means that the data associated with the arrow does not need further understanding (or need to be modeled) on the next-level child decomposition IDEF0 diagram. System Architect will not automatically add tunneled arrows to a child IDEF0 diagram.
Example
The graphic below illustrates how ICOMs are used with a single function. The Operate Warehouse function takes Customer Order as an input, uses Inventory and Customer as Controls, uses Materials Management and Carrier as Mechanisms (mechanisms can be thought of as "resources"), and has outputs of Purchase Orders, Shipments, and Order Confirmations.
