4/27/2004Extending SP95 for Batch Scheduling Extending ISA SP95 for Batch Scheduling by Steve Morrison, Ph.D. Chem. E. [email protected]

4/27/2004 Extending SP95 for Batch Scheduling

Extending ISA SP95 forExtending ISA SP95 forBatch SchedulingBatch Scheduling

bySteve Morrison, Ph.D. Chem. E.

[email protected]


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


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?


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?


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


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


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


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


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


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


Personnel – positions, not individuals

Process segment – Temporary or permanent grouping of equipment, materials, and personnel

Other SP95 Production Capabilities


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-


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


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


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

*

*

**

*

*


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


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


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.


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.


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


The Shortcoming of Data Historians

They all run out of data!


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


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?


(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


(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


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


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


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


If you have questions later, feel free to contact me at:

[email protected]

Questions?

Documents

4/27/2004Extending SP95 for Batch Scheduling Extending ISA SP95 for Batch Scheduling by Steve Morrison, Ph.D. Chem. E. [email protected]