Editing Hold Modules
modules belong to the Advanced Process
template (if you cannot find this template you may need to attach it
). After you have added a Hold
module by dragging it onto the flowchart view, you can edit it by double clicking. You can change the Name
of course, but the main functionality is determined by the Type
. There are 3 types of Hold
module and we will discuss each one of them separately.
Wait for Signal
This hold stores entities in a queue until a unique signal is recieved during the simulation. Each time the signal is received an entity leaves the Hold
Consider the example of simulating cars queing at a parking building exit while waiting for their prepaid parking tickets to be approved. The cars ( entities
) must wait for the signal 10 to be sent in the simulation. When this signal is sent, one car will proceed through the exit.
Scan for Condition
This hold stores entities in a queue until a condition is satisfied. However, the Hold
module ONLY checks this condition WHEN A CALENDAR EVENT OCCURS. If the condition is true then the first entity in the queue may leave the Hold
module. This generates a new event and the condition is checked again. Each time the condition is true an entity leaves the Hold
Below is an example of a Scan for Condition Hold
module from the Case Study: Courier Service Model.
This hold stores entities in a queue infinitely while the simulation is running.
An infinite hold is usually combined with a Search
module and a Remove
module (See Arena help for more details).
Consider the example of simulating an emergency waiting room. Incoming patients (entities) are placed into a queue based on their Patient Type. Patient Type is an attribute assigned to each entity earlier in the model. Entities will wait in the Emergency Room module in queue until they are removed from the queue by an nurse (entity) from a Remove module.
- 25 Aug 2009