4/27/2004Extending SP95 for Batch Scheduling Extending ISA SP95 for Batch Scheduling by Steve...
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Transcript of 4/27/2004Extending SP95 for Batch Scheduling Extending ISA SP95 for Batch Scheduling by Steve...
4/27/2004 Extending SP95 for Batch Scheduling
Extending ISA SP95 forExtending ISA SP95 forBatch SchedulingBatch Scheduling
bySteve Morrison, Ph.D. Chem. E.
4/27/2004 Extending SP95 for Batch Scheduling
SP95 in light of the S88 Standard
SP95 Product Definition
SP95 Production Capability
SP95 Production Information
Additional Classes for SP95
Role of Materials, Connections and Campaigns
History vs. Schedule Objects
Extending SP95 Objects for Batch SchedulingExtending SP95 Objects for Batch Scheduling
4/27/2004 Extending SP95 for Batch Scheduling
1. What’s a Unit?
a) A process area: a collection of equipment
b) A collection of operations that must run on the same equipment
A Test of S88
2. Which recipe makes the actual batches?
• general b) master c) control3. What is the lowest granularity of execution
a) unit b) operation c) phase d) other
4. What acquires and releases resources?
4/27/2004 Extending SP95 for Batch Scheduling
S88 Was a great step forward for common batch definitions, but…
Overkill for many plants and mills. Do batch plants all need General Recipes and Site Recipes for Control Recipes?
Even control recipes were not made for continuous aspects. SOC’s SOP’s, and Product Production Rules are better for many of those.
Since We Have S88, Why SP95?
4/27/2004 Extending SP95 for Batch Scheduling
How many batch plants do not have a single piece of equipment that is continuous?
S88 did not specify many things: materials, lots, process segments, tests, equipment classes, work cells, personnel, history, etc.
More S88 Shortcomings
4/27/2004 Extending SP95 for Batch Scheduling
Batch – S88 or other recipesGeneral – Chemist’s recipeMaster – quantities, resource candidatesControl – all choices and durations. Can be
reused, so not exact times
Continuous – SOP or SOC
SP95 introduces Product Production Rules as an option
SP95 Product Definition
4/27/2004 Extending SP95 for Batch Scheduling
G,M,C Recipe
G,M,C Unit
G,M,C Operation
G,M,C Phase
Equipment (unit level)
Equipment (non-unit
level)
Material
Personnel
Pipes, Manifolds,
Connectors
SP88 Classes
4/27/2004 Extending SP95 for Batch Scheduling
Product Production
Rule
Product Segment
Product Segment
Execution Order
Process Segment Material
Sublot
Equipment
PersonnelPipes,
Manifolds, Connectors
( temporary or permanent )
( all types )
Product Production Rules
4/27/2004 Extending SP95 for Batch Scheduling
The Enterprise has Sites, containing Areas, which contain Equipment and other items
Continuous Production Units, batch Process Cells, and repetitive Production Lines
Equipment – dedicated (unit) and non-dedicated (non-Unit) distinction is lost
No intermediate objects (non-dedicated pumps, centrifuges, washers, filters, manifold rooms)
SP95 has equipment maintenance objects too
SP95 Production Capability
4/27/2004 Extending SP95 for Batch Scheduling
Material – batch centric, not schedule centric.
Is an intermediate product a material consumed or a material produced? (pick only one!) - causes problems with global planning
Material definition vs. material lot vs. (recursive) material sublots
SP95 Materials
4/27/2004 Extending SP95 for Batch Scheduling
Personnel – positions, not individuals
Process segment – Temporary or permanent grouping of equipment, materials, and personnel
Other SP95 Production Capabilities
4/27/2004 Extending SP95 for Batch Scheduling
What is Needed to Schedule
Production Requests
(in a Schedule)
ProductionRules
(Recipes)
Production Capabilities
(Siteresources)
Production Responses
(History)
Past
Current
Future
Maintenance?
actuals
requirements
specifications-
4/27/2004 Extending SP95 for Batch Scheduling
Enhancements to SP95
Materials – MRP II typically materials only. Equipment often more important than material in a plant. Need equipment and materials together. Inventory vs. rate, spikes
Connections – Requirements and Capabilities – homogeneous vs. heterogeneous
4/27/2004 Extending SP95 for Batch Scheduling
Production Request Enhancements
Campaigns – Campaign lead time, end buffer, setup, startup, and cleanup times. Prior steps, yield and stoichiometry, feed inventory, global planning impact, multiple successor campaigns, and batches within campaigns.
Orders for grouping campaigns.
i.e. Production Requests need multiple levels of dependencies on other production requests
4/27/2004 Extending SP95 for Batch Scheduling
PersonnelClass
Person Property
MaterialDefinition
Person
Material Sublot
MaterialLot
Qualifica-tion Test
Spec.
Qualifica-tion Test Result
QA Test Result
MaterialLot Prop.
Equip.Class
Equip. Property
Equip-ment
Production Unit
Equip. Capability Test Spec
Equip. Cap. Test
Result
WorkCell
Production Line
MaterialClass
MaterialDef. Prop.
QA Test Spec.
MaterialClass Prop.
PersonnelClass Prop.
Equip.Class Prop.
Process Cell
Unit
AreaSiteEnterprise
Connect-ion
Manifold
Pipe Segment
Conveyor Tripper Car
Production Schedule
Product Definition
Campaignor Run
Consum-able Mat’l
S88 MasterRecipe
SOP (Std. Op. Proc.)
SOC (Std. Op. Cond.)
Production Request
Production Performance
Production Response
Segment Response
Process Segment
Equip. Actual
Personnel Actual
Consum-able Actual
Material Actual
Produc-tion Data
Material Task
Person Task
Equip. Task
Connec-tion Task
Consum-able Task
Batchor Lot
Connec. Actual
BatchUnit
Product Production
Rule
Consists of multiple equip-ment, connectors person, material sublots, and consumables
Product Segment
Product Segment
Execution Order
*
*
**
*
*
4/27/2004 Extending SP95 for Batch Scheduling
1. Instead of tasks, why not just use the SP95 requirement objects?
You can, if you make additions and change the intent of some of the classes.
2. Why not just use history objects for scheduling?
These could be the same, except that the attributes, states, methods, and lifecycle are different. SP95 was right to separate them.
Questions on Proposed Enhancements
4/27/2004 Extending SP95 for Batch Scheduling
SP95 Production Schedule Objects
SP95 has a family of requirement objects for equipment, material produced, material consumed, consumable expected, and personnel, which are all children of the segment requirement
Interestingly, only the segment requirement has timing information.
Furthermore, the only timing information it has is Earliest Start Time, Latest End Time, and Duration
4/27/2004 Extending SP95 for Batch Scheduling
Problems Using Segment Requirements
1. The timing information only being in the segment requirements is probably fine for process segments (in recipes) and segment responses (in history), but is not sufficient for a robust schedule.
2. The only timing information is Earliest start time and Latest end time. Also required is Planned start and end time, and (depending on the architecture) Actual start and end time.
4/27/2004 Extending SP95 for Batch Scheduling
Problem with Time Only in the Segment
Does the segment start if one resource it requires is not yet available?
Are the other resources free for others to use while waiting for the latest segment?
It might be time for the segment to run, except that it is in a waiting for resource state.
Different resources might be assigned to the segment at different times, even though everything in the segment only runs at the same time.
4/27/2004 Extending SP95 for Batch Scheduling
Enhancing Requirements (Tasks)resource Class Resource specification
Resource Segment Requirement
Description UID (primary key)
Quantity Predicted StartTime
Quantity Unit of Measure Predicted Duration
… the following for materials Planned StartTime
Material Lot Planned Duration
Material Sublot Constraints absolute/relative Start, Delay
Location
4/27/2004 Extending SP95 for Batch Scheduling
The Shortcoming of Data Historians
They all run out of data!
4/27/2004 Extending SP95 for Batch Scheduling
History objects show what has happened, and what is happening (in cases like batches that have started but not ended yet.)
Schedule objects show what is happening, what will happen. Some future events are too near the present to change.
Other future events are changeable and need to be scheduled in detail.
Farther in the future events need to be seen and scheduled, but CANNOT be optimally scheduled in detail
History vs. Schedule Objects
4/27/2004 Extending SP95 for Batch Scheduling
Schedule changeable horizon, short-term scheduling horizon, vs. long term scheduling horizon
Planned vs. Actual: Comparison of the values, as well as what is anchored.
Heavy-weight schedule objects vs. lightweight history objects
What-if scheduling: Multiple similar copies of the same future batch information.
Archival: Only past history need for last five years or more.
Why Not Combine History & Schedule?
4/27/2004 Extending SP95 for Batch Scheduling
(Control) Product ProductionRule Product Production Rule
NonOptimal DeltaTime
StartTime (can be blank) Start Time
End Time (can be blank) Source for Start Time
Planned Duration End Time (can be blank)
ArtificialCostForTheBatch Source for End Time
BatchStartDelay
(implicit) DelayComments
(implicit) IsFeasible
Batch Example : Schedule vs. History
4/27/2004 Extending SP95 for Batch Scheduling
(Actual or hypothetical) [Control] ProcessSegment
(Actual) SegmentResponse
NonOptimal DeltaTime StartTime
StartTime (can be blank) Source for StartTime
EndTime (can be blank) EndTime (can be blank)
PlannedDuration Source for End Time
ActDuration = End – Start ActDuration = End – Start
Anchor -duration, start, end (implicit) Corrector
(implicit) Anchor comments
ArtificialCostPerMinute
ArtificialCostToUse
AvailableSlackTime
(implicit) IsFeasible
Equipment Schedule vs. History
4/27/2004 Extending SP95 for Batch Scheduling
Planned vs. Actual: Multiple plans
Long term What-if: order changes, re-prioritizing campaigns, fulfilling production at different sites, and buying new equipment.
Short term What-if: Simulate the best options when a batch is delayed or equipment breaks down. This helps to quickly view alternatives and minimize scheduling mistakes.
Scheduling Distinctives
4/27/2004 Extending SP95 for Batch Scheduling
Cross-Batch Comparisons: For the same material, why do some batches take longer than others?
Plant Comparisons: Even with somewhat similar equipment, why are some plants better than others at making the same product?
More Scheduling Distinctives
4/27/2004 Extending SP95 for Batch Scheduling
SP95 is a good starting point for scheduling, because scheduling was considered in the standard.
However, a number of scheduling objects need to be added, because SP95 history objects are no replacement for scheduling objects.
For many types of scheduling SP95 also needs to be enhanced in the areas of Materials, Connections and Campaigns
Summary of SP95 Enhancements
4/27/2004 Extending SP95 for Batch Scheduling
If you have questions later, feel free to contact me at:
Questions?