- Introduction and overview
- Quick Start guide
- Setup and configuration of Sequencer
- Defining value profiles
- The Optimizer
- Known Limitations
This document explains how to setup, configure and use the Sequencer module.
Introduction and overview
The sequencer module in ROB-EX Scheduler consists of several enhancements for advanced planning and optimization.
A fundamental building block of the sequencer is that it allows advanced control of how to calculate the individual work time steps of an operation (setup, workload, switchover, etc.) and how to calculate the operation capacity (production rate). In short the above values can depend either on the resource they run on or they can depend on previous or next product planned on the same resource. Examples are:
- Variable workload or variable capacity according to operation/resource matrix lookup. E.g. the capacity is looked up based on resource name and product name:
- Variable setup and/or switchover time according to previous or next operation on the same resource. Eg. the setup time of the current operation is dependent on the product produced immediately before on the same resource.
- Lookup matrix/tables can be defined in either Excel spreadsheets or in SQL database tables.
In addition the Sequencer module allows interdependencies of operation start/end times for operations in the same route. An example of this feature is:
- Automatically recalculate operation to always end according to the end time of an operation later in the same route. This is useful if a resource should remain occupied until the planned finish date of an operation later in the route. In the example below the red operation has its switchover time updated to ensure the red operation always ends at the same time the green operation ends!
Finally the Sequencer contains a build in optimizer which can optimize the sequence of operations on of a single resource with respect to setup time, switchover time, order priority and delivery time.
All the above features are easy to use and configure.
Important Sequencer terms and concepts
|Work time step||any of the Operation steps: setup time, workload, switchover time, previous/post queue time and transport time|
|ValueProfile|| A named object defining for one or more work time steps how source values are read and the calculation rules to apply on the source values
Custom ValueProfiles can be programmed using the ROB-EX Scheduler API Developers Kit.
|ValueProvider|| Used by a ValueProfile to determine how to calculate a certain work time step or operation capacity. As an example a ValueProfile may have one ValueProvider deciding how the setup time is calculated and another ValueProvider deciding how switchover time is calculated.
Certain predefined types of ValueProfiles are available, e.g.
Quick Start guide
To quickly get started using sequencer there is a set of ready to use example files in the
<sch_client_dir>\data directory of the ROB-EX Scheduler Client installation:
- ValueProfiles.xml: This defines three ready to use value providers and value profiles
- sequencerIntro.xlsx: this Excel spreadsheet contains two sheets with setup and capacity matrix tables for LookupTableValueProviders, used by the ValueProfiles configured in ValueProfiles.xml.
- ganttintroSequencer.xml: A ROB-EX Scheduler planning file preloaded with master data matching the value profiles defined in ValueProfiles.xml.
To get started with the sequencer intro plan do the following:
- Make sure your ROB-EX Scheduler client has the Sequencer Option and the Macro Option licensed. Check the menu “Help->Register”.
- Copy the ValueProfiles.xml file from the “data” directory to the “custom” directory of your ROB-EX Scheduler install dir. After copying the file make sure ROB-EX Scheduler is restarted since the file custom\ValueProfiles.xml is only read once during start of ROB-EX Scheduler.
- From the ROB-EX Scheduler client open the ganttintroSequencer.xml plan using “File->Open…”.
- Verify that ValueProfiles.xml have been correctly loaded. In the menu “Edit resource” select the “Grinder 1” resource in the left resource tree. On the tab “Scheduling” click the option “Operation value profile” and make sure the following options are listed:
If only the option “No conditional values” are listed it means you have not correctly copied the ValueProfiles.xml file from the
datadirectory to the
customdirectory of your ROB-EX Scheduler install dir. Go back to step 2.
With the demo file loaded into the client 4 different key concepts of the Sequencer can be demonstrated.
1. Variable capacity based on product and resource
This example will demonstrate how operation capacity (production rate) is looked up based on the product produced and the resource an operation is assigned to. The matrix defining the combination between product and resource is defined in the Excel file data/sequencerIntro.xlsx in sheet “ProductResourceCapacity”.
To enable the “Cutting capacity profile” for all operations on Saw 1 and Saw 2 do the following:
- Go to Edit->Resource and choose Saw 1
- In the Scheduling tab change the Operation value profile to “Cutting capacity profile”
- Repeat step 2 for Saw 2.
Now try to change the selected resource for an operation on Order 1001 from Saw 2 to Saw 1 and observe how the duration of the operation changes because the move triggers a change in operation capacity. Next edit values in Excel file data/sequencerIntro.xlsx for the sheet “ProductResourceCapacity”. In order for ROB-EX Scheduler to pick up any change in the Excel file the ROB-EX Scheduler client must be restarted !
2. Adjust operation end time to packaging operation end
This example will demonstrate the interdependency feature of the Sequencer option, by adjusting operation end on one operation to planned finish time of the packaging operation.
The ValueProfile “Switchover ends at packaging” as setup in ValueProfiles.xml will adjust the switchover of the operation, so the operation ends when at the planned finish time of the packaging operation. If the route does not contain any packaging operation, the switchover time will always be zero.
To see how this value profile works do the following:
- Find operation “Painting” in order 1005 (last operation on resource “Paint cabin”).
- Double click the operation and verify that the “Anchor out” is set to “Switchover start”.
- Click the “Advanced” tab
- Deselect the “Use value profile from resource” checkbox.
- In the “Operation value profile” dropdown box choose the “Switchover ends at packing” value profile.
In the plan the painting operation now ends when the packaging operation ends, notice how the switchover time is adjusted.
Try moving the painting operation and observe that the operation always ends when the packaging operation ends. Try moving the packaging operation and observe that the end of the painting operation follows the packaging operation.
3. Setup time depends on previous product on the same resource
This example will demonstrate how setup time on one operation depends on the product produced on the previous operation on the same resource. The matrix defining the combination between product and product is defined in the Excel file data/sequencerIntro.xlsx in sheet “ProductProductSetup”.
The value profile “Sequence dependent setup” will adjust the setup time depending of the product to product sequence.
To see how the “Sequence dependent setup” value profile works do the following:
- Go to Edit->Resource and choose Saw 1
- In the Scheduling tab change the Operation value profile to “Sequence dependent setup”
- Repeat step 2 for Saw 2.
Observe how some of the operations on Saw 1 and 2 now have setup times. Try moving the operation back and forth in time and see how the setup time changes depending on the sequence of the operations.
4. Running the Optimizer
Once the “Sequence dependent setup” value profile is selected on Saw 1 and Saw 2 it is possible to run the optimization algorithms for each resource:
- With the mouse select all operations on Saw 1
- Create a macro to run the optimizer. In the menu select “Functions->Macro->Edit” create a new macro and add the “SequenceOptimizer” command to the macro. Setup the macro or just use the default values, also see the manual of the SequenceOptimizer macro command.
- Run the macro
- The optimizer runs for a short time and the operations are updated to the best found sequence that minimizes setup time. Color by route colors to best visualize product colors.
Repeat the steps for Saw 2 to optimize the operation sequence on this resource. Also try moving all operations from Saw 2 to resource Saw 1 in order to optimize on more operations at the same time.