Now lets make the simulation a little more complicated. SA Simulator II allows for the simulation of leveled diagrams – diagrams for which you have decomposed processes with ‘child’ diagrams that show more intricate detail.
For this tutorial we will attach a child diagram to the process symbol called Ensure Stock. This diagram will specify, in detail, the process of ensuring we have enough stock. This is an important part of the order process – we must make sure we have enough stock to fill all of the incoming orders, otherwise those orders cannot be filled. What happens in this Process Flow will affect the entire order process.
For your convenience, the Process Flow diagram Ensure Stock has already been created. All you need to do is attach it to the Ensure Stock process symbol as a child diagram.
1 With the Orders diagram open and in focus, select the Ensure Stock process symbol.
2 Right-click the Ensure Stock process symbol, and then select Child Attach from the floating menu to open the Select for Attaching dialog.
3 Select the Ensure Stock (IDEF3 Process Flow) diagram, and then click the Attach button.
4 You will be prompted to save the changes on the parent diagram, Orders. Click Yes.
The child diagram automatically opens as shown below:
Review the ‘child’ IDEF3 Process Flow Diagram
1 Review the Process Flow diagram itself. On this diagram we have modeled that:
•The company analyzes its supply to see if there is enough stock on hand to meet the order.
•Goods are then assigned to the order.
•Junction J3 is a simple OR gate – we have placed it in the flow to model a feedback loop that we will discuss later. Either the flow coming from Assign Goods to Order, or the flow coming from the feedback path goes through the OR junction unimpeded.
•Junction Order Filled? asks whether or not enough stock was on hand to fill the order. If not, the Process Flow goes through a sub-flow wherein the particular item(s) missing are reordered, the customer is notified that the order is being delayed, and we wait for a new supply shipment for the order to be filled.
•In the diagram, Wait for Supply is colored grey. We have colored this differently for a reason. In the next step we will see why.
2 Open the ‘Wait for Supply symbol’s definition’ dialog. Observe on its Sim Definition tab that its Simulation Type is specified as Hold. On the Sim Hold tab of this process, observe that Minimum Delay Length is set at a Constant of 2 days. We have modeled that a new shipment comes in every two days. A shipment for which there is not enough stock to meet the order will be held up for that long.
3 Continue reviewing the diagram.
•When the shipment arrives (after the Wait for Supply process completes), the materials are checked to see if the items necessary to fill the order have arrived.
•The order is filled and the remainder of items in the shipment are added to the company’s supply.
•The flow feeds back into the main flow, through the J3 OR junction mentioned previously.
•If the output of the Order Filled junction is yes, the order is sent to the Order Filled process.
4 Open the Definition dialog of the Order Filled process. Select the Sim Definition tab.
Note This process is of type Result.
5 Click the Sim Result tab of the ‘Order Filled process definition’ dialog.
Note The Pass Objects (Terminate) property has been toggled ‘on’. This means that the objects reaching this result are passed back up to the parent diagram. This is a very important property to toggle ‘on’ for this diagram set to be simulated properly.
Validate the diagram for simulation
1 Validate the child diagram by selecting Tools > SA Simulator > Validate Simulation.
2 Review the report that is displayed.
The validation report indicates that there are no simulation parameters and that the Check Order event symbol is missing an Object. All Event symbols must generate an object, therefore we must assign an object to this event.
