3.9 – Storages
Storages are waiting areas, stock places, etc. where entities can wait for further processing. Storages are useful when controlling the order in which entities are allowed to move on through the model. Since an activity provides the option to have a built-in input and output queue, a storage is for visual purposes or to model special queuing conditions such as multiple activities sharing a common input queue.
3.9.1 – General
Name The name of the storage (e.g. StockRoom ).
Capacity The maximum number of entities that can occupy this storage (1 – 999,999). Scenario Paramenters may also be used in this field.
Queuing order The order in which entities are queued to leave the storage: none, first-in first-out, last-in first-out.
• None — Entities that have completed their Action Logic are free to process any routing logic independent from other entities that have finished their Action Logic. Will process FIFO if no other routing requirements are enforced (i.e. Conditional Routes, Get with a priority, etc.).
• First In, First Out (FIFO) — The first entity completing its Action Logic must be routed first.
• Last In, First Out (LIFO) — The last entity completing its Action Logic must be routed first.
Object Type Allows the type of object to be changed from Storage to something else.
3.9.2 – Action
Action Develop customized behavior for entities at an storage. Logic can be developed to report statistics, control processing, collect information and a host of other items. Variables, entity attributes, systems information and if-then statements allow expansive capabilities to be accessed from the action tab. For additional information see Section 3.11, Action Logic.
3.10 – Schedules—Shifts & Breaks
3.10.1 – Shift Definition
Weekly shifts and breaks for activities and resources are defined using the Shift editor and may start and end at any minute of the day. Defining shifts for resources and activities in a model is only necessary when there are activities or resources with different work schedules. Otherwise the simulation can be run for a single block of time as though there was no off-shift time.
Shifts and breaks are defined by blocking out sections of time on a grid divided into days and hours. Once a weekly shift and break schedule has been defined, it may be saved in a shift file, which has an.SFT extension. This allows you to use the shift definition in models you create later.
This screen shot of the Shift Editor shows a shift defined to begin at 8 a.m. and end at 4:30 p.m. with two short breaks and a lunch break.
If the shift file opens blank but the model simulates correctly, make sure the file path is shorter than 255 characters.
The shift file in a resource’s Shift tab can not be changed as conditions change in the simulation. Each resource can only have 1 shift for the entire simulation run. An attribute, variable, or scenario parameter can however be checked in the action logic. Then based on that parameter’s value, The appropriate resource with the desired shift can be selected.
How To – Open the Shift Editor
1. Open the Options dialog from the Simulation menu and click on the Files tab.
Click on the Shift tab of the properties dialog when a resource or activity is selected.
2. Click on the Create Shift File button.
The Shift editor consists of a menu bar, Shift and Break mode buttons, time control buttons, and a grid representing one week of time. (All shown on the previous page.)
The remainder of this section describes the Shift Editor menus and the following procedures:
• Drawing a Block of Time for a Shift or Break
• Selecting a Block
• Resizing a Block
• Editing the Begin or End Time
• Deleting a Block
• Duplicating a Specific Day’s Shift
• Customizing Shift and Break Colors
Shift Editor Menus
The menus used in the Shift editor are accessible from the menu bar at the top of the editor and include the following:
File For opening shift files and saving open shift files.
Edit For deleting unwanted shift and break blocks. You may also duplicate a specific day of the shift. If you delete a shift, it deletes the shift as well as the breaks in the shift.
View For access to status and tool bars.
Options For customizing the colors which represent shifts and breaks.
Defining & Editing Shift & Break Blocks
You define a shift by selecting the Shift tool and drawing a shift block for each day that is to represent time on the shift. The break block tool can then be selected to draw break blocks over any portion of the defined shift. A break differs from off-shift time in that if a resource or activity is busy when a break time is scheduled to occur, the duration of the break time remains unchanged even if it could not immediately take effect. Off-shift time, in contrast, is reduced by any delay in going off shift, i.e., the activity comes back on shift at the scheduled time regardless of any delay in going off shift. This behavior typifies most real world situations.
When drawing a shift or break block, you must be sure to follow these rules:
• Shift blocks may not overlap with other shift blocks.
• Break blocks may only be drawn on top of shift blocks.
• Break blocks may not overlap or be adjacent to other break blocks.
How To – Draw a block
1. Click on the Shift or Break button to designate the type of block.
2. Begin dragging the mouse on the grid at the day and time that the block should begin.
3. Release the mouse button at the time that the block should end. If you want to define a block more precisely than the grid allows, see Editing the Begin or End Time below.
If the block you draw is invalid, it is ignored and will not appear on the time grid.
How To – Select an existing block
• Click on the block. A border appears to show that the block has been selected.
How To – Deselect a block
• Click on the selected block or click on the white area of the window.
How To – Resize a block
1. Select the block.
2. Click and drag the border of the block until the block is the desired size.
3. Release the mouse button.
How To – Edit a block’s begin or end time
1. Select the block.
2. Adjust the begin or end time accordingly using the buttons at the top of the screen. Click on the part of the time display you want to change (the hour, the minutes, or the AM/PM label). While that part of the display is highlighted, use the arrow buttons to increase or decrease the time, or to switch between AM and PM.
How To – Delete a block
• Select a block and choose the Delete option from the Edit menu.
• Select a block and press the Delete key on the keyboard.
How To – Duplicate a shift block from one day to another day
1. Select any shift or break segment for the day you wish to duplicate.
2. Select Duplicate button from the toolbar.
3. In the shift schedule, click on the day to which you wish to copy the shift block.
To duplicate the same shift multiple times, hold the SHIFT key down while clicking were the shift is to be duplicated. Release the SHIFT key on the last duplication to exit the duplication mode.
How To – Change the color for shifts or breaks
1. From the Options menu, select Define Shift or Define Break.
2. Choose Colors under the Options menu. The colors dialog box appears.
3. Click on the desired color.
3.10.2 – Shift Assignments
Once one or more shift files have been defined, resources and activities may be assigned to these shift schedules in the model. To designate a particular shift as the default shift for all activities or resources, see Default Shift File. To override the default shift, you may assign a shift schedule to a particular resource or activity in its properties dialog. If different units of the same resource have a different schedule, they should be defined as separate resource types (e.g. Shift1_operators, Shift2_operators).
How To – Assign shift schedule to a resource or activity
1. Select the resource or activity on the layout. (Double click if the properties dialog has been closed.)
2. Click on the Shift tab to display the shift schedule properties.
3. Enter the name of the shift file or use the Browse button to find the file. Or click on the Create shift file button to create the file and return to enter the name.
4. Check the Interrupt current activity to go off shift or on break box if the activity or resource is to be interrupted, if busy, in order to go off shift or on break. If not checked, the priority is 99 which is the highest non-interruptive priority, meaning that the activity will finish processing the entity or the resource will complete its assignment before going off shift or on break.
Default Shift File
The Files tab on the Options dialog accessed from the Simulation menu allows you to specify a default shift file for activities and a default shift file for resources. A default shift file may be overridden by selecting a different file in the properties dialog for that specific activity or resource.
How To – Define a default shift file for activities or resources
1. From the Simulation menu, select Options and select the Files tab in the dialog.
2. Select Default Activity Shift File or Default Resource Shift File , then click on the Create shift file button.
3. Create a shift file following the instructions in Shift Definition.
4. Enter the name of the shift file in the File Name field.
5. Check the Interrupt activity/resource to go off shift or on break box if activities or resources that are currently busy are to be interrupted in order to go off shift or on break. If not checked, the priority is 99 which is the highest non-interruptive priority.
6. Click on the Close button when finished.