---
description: Stop an in-process Material exceptionally using the Abort feature of the OPC UA Standard.
alias: userguide-equipment-integration-opcua-standard-abort
---

# Abort

## Overview

**Abort** stops an in-process Material exceptionally. Use **Track Out** for normal completion. MES applies the standard **Abort** rules, including Material state and process restrictions.

See [Abort Material](https://help.criticalmanufacturing.com/userguide/business-data/material/abort_material_process/) for the product transaction behavior.

## Nodes

| Relative node                               | OPC UA type | Direction     | Purpose                             |
| ------------------------------------------- | ----------- | ------------- | ----------------------------------- |
| `Operation.Abort.Material.Name`             | `String`    | Machine → MES | Exact MES Material name            |
| `Operation.Abort.MachineOperationRequest`   | `Boolean`   | Machine → MES | Starts machine-initiated **Abort** |
| `Operation.Abort.MESOperationPerformed`     | `Boolean`   | MES → Machine | Indicates that MES performed **Abort** and is waiting for machine confirmation |
| `Operation.Abort.MachineOperationConfirmed` | `Boolean`   | Machine → MES | Machine consumed the result        |

## Communication Flow

```mermaid
--8<-- "docs/userguide/equipmentintegration/opcua-standard/_includes/mermaid-sequence-theme.txt"
sequenceDiagram
    autonumber
    actor O as Operator
    participant M as Machine / OPC UA Server
    participant I as Connect IoT
    participant E as Critical Manufacturing MES

    alt Machine initiated
        M->>I: Material.Name
        M->>I: MachineOperationRequest = true
        I->>E: Abort resolved in-process Material
    else Operator initiated
        O->>E: Abort selected Material in MES UI
    end

    E->>E: Validate and perform Abort within transaction
    E-->>I: Abort performed, awaiting machine confirmation
    I->>M: MESOperationPerformed = true

    alt Confirmation before MachineReplyTimeout
        M-->>I: MachineOperationConfirmed = true
        I-->>E: Machine confirmed
        E->>E: Commit Abort
        I->>M: MESOperationPerformed = false
        M->>I: Machine-owned bits = false
    else MachineReplyTimeout expires
        I-->>E: Machine confirmation timeout
        E->>E: Roll back Abort
        I->>M: MESOperationPerformed = false
    end
```

## Step-by-Step Process

### Machine-Initiated

1. The PLC writes `Material.Name`.
2. The PLC sets `MachineOperationRequest = true`, which raises the machine request through Connect IoT.
3. Connect IoT requests **Abort** in MES and provides the explicit Material name when available.
4. MES resolves the explicit Material or, when FIFO is enabled, the first eligible in-process Material at the Resource.
5. MES validates and performs **Abort** within the current transaction.
6. Connect IoT sets `MESOperationPerformed = true` and waits for `MachineOperationConfirmed = true`.
7. When confirmation arrives before `MachineReplyTimeout`, MES commits **Abort**.
8. Both sides return their control bits to `false`.
9. If confirmation does not arrive in time, **Abort** fails and the transaction rolls back.

### Operator-Initiated

1. The operator selects the Material and performs **Abort** in the MES UI; `MachineOperationRequest` is not required.
2. MES validates and performs **Abort** within the current transaction.
3. Connect IoT sets `MESOperationPerformed = true` and waits for the machine confirmation.
4. When confirmation arrives before `MachineReplyTimeout`, MES commits **Abort**.
5. The result and confirmation bits are reset.
6. If confirmation does not arrive in time, the operator receives a failure and the transaction rolls back.

## Safety Boundary

The MES **Abort** transaction does not replace machine safety functions. Emergency stop, interlocks, safe motion, and energy isolation remain machine responsibilities. The OPC UA handshake communicates manufacturing execution state.

## Failure Behavior

- In MES automation controller type must be `IndEqController`
- In MES resource `EnableAutomationScenarios` must be set to `true`
- A Material that is not in process at the Resource is rejected.
- If MES rejects **Abort**, `MESOperationPerformed` remains `false` and the reason is logged.
- If the machine does not set `MachineOperationConfirmed = true` before `MachineReplyTimeout` expires, **Abort** is not successful and its transaction rolls back.
- After a timeout, reconcile the MES Material state, machine state, and handshake values before retrying.

## Validation and Assumptions

- [ ] Only eligible in-process Materials can be aborted.
- [ ] Operator-initiated **Abort** notifies the machine without a machine request when `EnableAutomationScenarios = true`.
- [ ] The physical machine outcome is defined for a successful **Abort** signal.
- [ ] Safety behavior does not depend on MES communication.
- [ ] Missing-acknowledgement recovery cannot execute **Abort** twice.
- [ ] Resource is set as `EnableAutomationScenarios = true`
- [ ] MES automation controller type is `IndEqController`