# BOM Pre-Check

!!! info "From SMT Template version 3.2.0 onwards"

## Overview

The BOM Pre-Check feature compares the component data received from Fuji's `BOMLIST` event with the material BOM stored in MES. This ensures consistency and accuracy before production begins.

## How It Works

### Data Preparation Step

The **BOMLIST** event is sent by Fuji when the PGCHANGEII event receives an acknowledge.

The Automation Controller will parse this event and store a list of **Reference Designators** with the corresponding **Product** in persistent storage using a key composed of equipment details:

`BOMLIST_{Equipment Line Name}_{Equipment Machine Name}_{Equipment Module Number}_{Equipment Lane Number}_{Equipment Program Name}`.

??? example "Placement List"
    ```JSON
        PlacementLists: '[
        {
            "ReferenceDesignator": "C1",
            "ComponentNames": [
            "SMT_Component_1"
            ]
        },
        {
            "ReferenceDesignator": "C2",
            "ComponentNames": [
            "SMT_Component_1"
            ]
        },
        {
            "ReferenceDesignator": "C5",
            "ComponentNames": [
            "SMT_Component_2"
            ]
        },
        {
            "ReferenceDesignator": "C3",
            "ComponentNames": [
            "SMT_Component_1"
            ]
        },
        {
            "ReferenceDesignator": "C4",
            "ComponentNames": [
            "SMT_Component_1"
            ]
        }
        ]'
    ```

### Validation Step

When a `PCBCHECKIN` event is received:

- The stored `BOMLIST` data is retrieved.
- It is sent as input to the service **`ValidatePlacementList`** for comparison against the current BOM material in MES.
  
[For more information about ValidatePlacementList check here.](../../../artifacts/services.md#validateplacementlist)

### Persistency Handling

After the first successful validation of the BOM, a key named **BomValidated_<Resource Name>** will be stored in persistency with the value true.
This allows subsequent requests to bypass validation until a new recipe is downloaded to the equipment.

If you need to trigger a new validation on the next board request event, you can send a message bus message to the Area configured for the OIB Controller. Use the action group `SMT.IoT.Utilities.ResetPreBomValidation` and include the `ResourceName` in the message body.

??? example "Show DEE Example"
    ```csharp
    UseReference("", "Cmf.Foundation.Common.Exceptions");
    UseReference("Cmf.Foundation.BusinessObjects.dll", "Cmf.Foundation.BusinessObjects");
    UseReference("Cmf.Foundation.BusinessOrchestration.dll", "");
    UseReference("", "Cmf.Foundation.Common.Exceptions");
    UseReference("", "Cmf.Foundation.Common");
    UseReference("Cmf.Navigo.BusinessObjects.dll", "Cmf.Navigo.BusinessObjects");

    var serviceProvider = (IServiceProvider)Input["ServiceProvider"];
    IArea area = serviceProvider.GetService<IArea>();
    area.Name = "SMT_Production Line";
    area.Load();

    var instance = area.GetAutomationControllerInstance();
    if (instance == null)
    {
        throw new Exception("Area not connected to any IoT instance");
    }
    else
    {
        var args = new
        {
            ResourceName = "SMT_Pick_Place_1"
        };

        instance.Publish("SMT.IoT.Utilities.ResetPreBomValidation", args.ToJsonString());
    }
    ```