---
alias: user-guide-automation-task-mes-materialtrackinrequest
tags:
- automation tasks
description: "Trigger task that listens for Material Track In requests from the MES and starts the equipment-side handling for the operation"
---

# On Material Track In Request

:iot-system-event-lg:

This **trigger** task listens for Material Track In requests coming from the MES and lets a workflow perform the equipment-side handling when an operator tracks a **Material** in at a **Resource**.

It belongs to the `System / MES` category, under `Triggers`, and is available in both Data Flow and Control Flow workflows. In a Control Flow workflow it appears as a `Start` trigger named `When a Resource performs Material Track In`.

![On Material Track In Request - Data Flow Task](./images/on_material_track_in_request-task.png)

## Details

| Fields            | Details                                                                            |
| ----------------- | ---------------------------------------------------------------------------------- |
| Scope             | Connect IoT <br> Data Platform <br> Enterprise Integration <br> Factory Automation |
| Workflow          | Data flow <br> Control flow                                                        |
| `IsProtocol` flag | :material-close:{style="color:#EF5350"}                                       |

## Behavior

When an operator performs [[user-guide-track-in-material]], the MES sends a request on the `ConnectIoT.TrackIn.RequestReply` subject and waits for a reply. This task receives that request, emits the `resource` and the `material` involved in the operation, and emits `Success`.

The MES sends the request only when the **Resource** involved in the operation has the Enable Automation Scenarios and Material Track-In Interlocking properties enabled. The request is handled by the Automation Controller instance associated with the Resource or, when defined, with its Automation Scenarios Owner Entity.

The MES stays blocked until a reply is sent. If none is sent within the `Reply Timeout`, the task emits `Error` and the track in fails on the MES side.

The reply is produced differently depending on the workflow type:

- **Control Flow** - the reply is the result of the trigger's handler branch.
- **Data Flow** - a downstream [Send Material Track In Reply](task_material_track_in_reply.md) task sends the reply.

## Inputs

| Name           | Data Type | Description                                                                                                            |
| -------------- | --------- | ---------------------------------------------------------------------------------------------------------------------- |
| Enable/Disable | `Boolean` | Enables (`true`) or disables (`false`) the message listener at runtime. Works together with the `Auto Enable` setting. |

Table: On Material Track In Request task inputs

## Outputs

| Name         | Data Type    | Description                                            |
| ------------ | ------------ | ------------------------------------------------------ |
| resource     | `Resource`   | The Resource where the operation is being performed.   |
| material | `Material` | The Material being tracked in.   |
| Success      | `Boolean`    | Triggered when a request is received and processed.    |
| Error        | `Error`      | Triggered when the task fails or the reply times out.  |

Table: On Material Track In Request task outputs

## Settings

On the `General` tab, you have the usual settings and the following settings:

| Name                     | Data Type | Values | Default                        | Description                                                                                     |
| ------------------------ | --------- | ------ | ------------------------------ | ----------------------------------------------------------------------------------------------- |
| Auto Enable              | `Boolean` |        | `true`                         | Automatically enables the message listener when the task starts.                                |
| Reply Timeout            | `Integer` | ms     | `60000`                        | Amount of time allowed to wait for a reply before issuing a timeout. This setting is mandatory. |
| Material Track In Request Subject | `String`  |        | `ConnectIoT.TrackIn.RequestReply` | Subject used to communicate with the MES. This setting is read-only.                            |

Table: On Material Track In Request task settings

![Settings Wizard for On Material Track In Request Task](./images/on_material_track_in_request-task_settings.png)

## Remarks

This task pairs with the [Send Material Track In Reply](task_material_track_in_reply.md) task, which sends the reply back to the originating request.

This task uses a specific structure of context-based data called `zone`. More information on this topic can be read in the [Zones](../zones.md) page.