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1.3 System Landscape & RACI

A manufacturing floor running on undefined system boundaries guarantees data corruption. When an ERP attempts to readmanage millisecond sensor data, or a PLC tries to query financial ledgers, the architecture suffers a "Singlesplit-brain" Sourcefailure ofwhere Truth"the disintegrates.financial view contradicts physical reality. You must strictly define the architectural layers based on Data Granularity and functionalFunctional domainDomain, ensuring every data point has exactly one Master Owner.

The System RACI Protocol

In a digital ecosystem, RACI does not apply to people; it applies to Databases.

  • Accountable (A): The System of Record. This holds the "Golden Copy." If this database is corrupted, the truth is lost. There can only be one Accountable system per object.
  • Responsible (R): The system executing the transaction or generating the raw data.
  • Consulted (C): Systems providing validation or constraints (e.g., PLM providing limits to MES).
  • Informed (I): Systems that subscribe to data updates (Read-Only).

The RACI Matrix

Data Object

ERP

PLM

MES

QMS

WMS

Bill of Materials (BOM)

I

A

I

C

–

Routing / Process

–

A

I

C

–

Production Order (WO)

A

–

R

–

I

Material Lots (Inventory)

A

–

R

–

R

Serial Numbers (UIDs)

I

–

A

–

–

Defects / NC

–

C

R

A

–

Rework Loops

–

C

A

I

–

The Core Trinity: ERP, MES, PLM

Modern manufacturing relies on three pillar systems. Do not force one tool to doperform the jobfunction of another.

ERP (Enterprise Resource Planning)

  • The Domain: Finance, Inventory, Procurement, and Order Management.
  • The Question it Answers:Question: "Why are we building this, and how much does it cost?"
  • The Boundary: ERP stops at the warehouse door. It knowsmanages youaggregate haveinventory (e.g., "1,000 screws,screws available") but itlacks doesvisibility not knowinto which specific screw wentwas intoinstalled in which specific product.

PLM (Product Lifecycle Management)

  • The Domain: Engineering Design, BOM (Bill of Materials),BOM, CAD, and Revision Control.
  • The Question it Answers:Question: "What are we building?"
  • The Boundary: PLM owns the definition. It creates the "Digital Twin" of the product structure. Itand pushes dataspecifications to ERP and MESMES. butIt never executes production.

MES (Manufacturing Execution System)

  • The Domain: Production Control, Quality, Genealogy, and Machine Connectivity.
  • The Question it Answers:Question: "How is it being built right now?"
  • The Boundary: MES executes the work. It isacts as the bridge between the digital definition (PLM) and the physical reality.

TheCritical SingleLogic Source& of Truth (SSOT)Boundaries

Do not rely on the table alone. You must implement the following logic gates to enforce the RACI.

1. Static Data duplication(BOM & Routing)

  • Owner (A): PLM.
  • The Risk: Manufacturing Engineers often tweak routings directly in the MES to "make it work." This breaks the revision loop with Engineering.
  • The Mandate:
    • If a process change is therequired enemy→ ofThen integrity. Establish a "System of Record" for every critical data object. Any other system that needs this datait must be released in PLM first.
    • If MES detects a BOM mismatch → Then enforce a "Subscriber,"Stop neverShip" anuntil editor.

      PLM pushes the Revision update.

The2. OwnershipDemand Matrix& Work Orders (WO)

  • CustomerOwner Demand:(A): OwnedERP.
  • The byRisk: Production planners creating "phantom orders" in MES to keep lines running without financial approval.
  • The Mandate:
    • ERP generates the Production_Order_ID.
    • MES is ERPResponsible (R).
      • Logic: Salesfor entersupdating the orderstatus in(Scheduled ERP.→ In_Progress → Complete).
      • MES seescannot itcreate asa "Scheduled,"WO. butIt cannotcan changeonly theconsume quantity or due date.one.

    3. Material Lots & Inventory

    • Product DefinitionOwner (BOM)A): Owned by PLM.
      • Logic: Engineers release Rev A in PLM. ERP calculates(Financial cost; MES validates assembly. If a shop-floor user changes a part manually in MES, the loop is broken. Value).Forbid this.
    • Unit HistoryExecutor (Genealogy)R): OwnedWMS by(Storage) / MES (Consumption).
    • The Logic:
      • If material is in the Warehouse → WMS controls location.
      • If material is issued to the Floor → MES.
           takes custody.
        • If material is consumed/scrapped → MES triggers the deduction transaction.
        • Then ERP passively receives the inventory decrement signal. ERP Logic:never guesses consumption based on BOM (back-flushing is forbidden for high-value components).

      4. Traceability (Serials & Defects)

      • Owner (A): MES.
      • The Risk: Storing serialization data in ERP bloats the database and slows down financial closing.
      • The Mandate:
        • MES generates the unique serial number (UID).
        • QMS ERPis onlyAccountable knowsfor thatthe "onedisposition of a defect (Use As Is / Scrap), but MES is Responsible for blocking the unit was finished." The MES holds the granular history (who, when, which machine).physically.

      Pro-Tip: BewareDo ofnot "Excelpush Glue."every Ifsingle yourscrew Criticaltighten Pathresult reliesto onERP. Push a spreadsheet"Genealogy managedSummary" by(Parent/Child alink) planneronly towhen translatethe ERPunit ordersis into MES schedules, your architecture has failed. The data flow must be automated and API-driven.shipped.

    Data Flow Strategy: Push vs. Pull

    Define how data movesmovement between the pillarsdirection to prevent synchronization lag.

    Master Data (Push)

    Static data (BOMs, Part Numbers, Users) shouldtriggers bea PushedPush from the Owner to theSubscriber Subscriberimmediately upon release.

    • Example:If PLM releases a new BOM ->→ TriggersThen immediatePLM pushes the update into ERP and MES.

    Transactional Data (Event-Driven)

    Dynamic data (Inventory Consumption, Status Updates) shouldoperates beon Event-Driven.Driven logic.

    • Example:
      • If Operator finishes a unit (MES Event) ->→ Then MES instantly decrements local WIP.
      • Then MES accumulates these events and sends a bulk "Production Declaration" to ERP (e.g., every shifthourly or hourly)per shift).

    Shadow IT and the "App Trap"Containment

    Well-meaning engineers often build isolated apps (PowerApps, SQL scripts) to solve local problems. While innovative, theseThese create "Dark Data" silos thatinvisible theto enterprise systems cannot see.systems.

    The Containment RuleRule:

    • If an app generates data required for audits (Quality Pass/Fail, Traceability) ->→ ItThen it must integrate directly with the MES.
    • If an app is purely for visualization (Dashboarding) ->→ ItThen canit read-onlymay Read-Only from the Data Lake.

    Final Checklist

    Data Object

    System of Record (Owner)

    Consumer (Subscriber)

    Critical Rule

    Sales Order

    ERP

    MES

    MES cannot create or delete orders.

    BOM / Route

    PLM

    ERP, MES

    Engineering Change Orders (ECO) start in PLM.

    Inventory ($)

    ERP

    MES

    ERP owns the asset value; MES owns the location.

    Unit Traceability

    MES

    ERP (Summary)

    MES owns the unique Serial Number history.

    Quality Limits

    PLM/MES

    Machines

    Machines execute limits; they do not define them.

    Costing

    ERP

    Sales

    MES sends "Time Spent" to ERP for cost calc.

    Equipment State

    MES/SCADA

    Maintenance

    Do not rely on ERP for machine downtime tracking.


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