Terminating and Deleting Blocked Control Recipes in SIMATIC BATCH when SFC Phases Hang

In SIMATIC BATCH, an active control recipe cannot be aborted or deleted if an underlying SFC phase or equipment unit is in an uncoordinated state (such as Manual mode, Held, or waiting on an unfulfilled interlocking transition). SIMATIC BATCH enforces strict state coordination between the recipe control strategy and physical equipment. To resolve a blocked recipe: first locate the stuck SFC phase in WinCC Runtime, place the phase into Automatic mode, and issue an Abort or Reset command from the SFC faceplate. If the phase remains unresponsive, open the UNIT_PLC (FB266) faceplate or parameter screen in CFC and trigger an equipment abort/release. Once all allocated phases report Idle or Aborted, abort the control recipe in BatchCC, close it, and proceed with recipe deletion.

Executive Summary

In SIMATIC BATCH architectures compliant with ISA-88, control recipes execute by coordinating physical controller logic via SFC Types, BATCH Interface Blocks (UNIT_PLC, BMOD, EPH), and WinCC Runtime. During abnormal operating events-such as equipment interlock trips, communication dropouts, or unauthorized manual operator interventions-a control recipe can become trapped in intermediate states such as 'Aborting', 'Holding', or 'Stopping'. When operating personnel attempt to force an abort or delete the control recipe directly from SIMATIC BATCH Control Center (BatchCC), the command is rejected by the batch state machine. This article explains the underlying state synchronization mechanisms between SIMATIC BATCH and the AS, clarifies why manual mode ('on hand') prevents recipe state transitions, and outlines the precise procedure for resetting phases, releasing unit allocations, and safely closing and deleting control recipes.

Architecture and Fundamental Mechanics

ISA-88 State Machine Synchronization and BATCH Interface Mechanics:

ISA-88 Hierarchical State Coordination:
SIMATIC BATCH couples recipe phase execution with the S7 controller SFC state machine (based on NAMUR NE33 and ISA-88 standards). A Recipe Operation (ROP) commands a Recipe Phase (EPH), which binds dynamically to an SFC Type instance running in the S7-400 AS.
When an abort command is initiated in BatchCC, SIMATIC BATCH does not simply purge the recipe record from memory. It issues an active state transition command (ABORT) across the communication channel (Batch Server -> WinCC OS Server -> AS via UNIT_PLC and phase interface blocks).
The recipe control strategy remains in the 'Aborting' state until all allocated recipe phases acknowledge transition into the terminal 'Aborted' state.
The 'On Hand' (Manual Mode) Blocker:
If an operator intervenes in WinCC Runtime and switches an SFC phase from Automatic to Manual ('Taking on Hand'), the controller decouples the SFC instance from supervisory batch control to ensure personnel safety.
In Manual mode, external commands issued by BatchCC (including ABORT and STOP) are ignored by the SFC Type logic. Because BatchCC waits indefinitely for the phase to report that it has completed its abort sequence, the control recipe hangs indefinitely in the 'Aborting' state.
Unit Allocation and UNIT_PLC Coordination:
Each technological unit in SIMATIC BATCH is represented in CFC by the UNIT_PLC block (FB266). UNIT_PLC tracks batch occupation parameters, including Batch ID (BA_ID), Batch Name (BA_NA), Step Number (STEP_NO), and active status (OCC_RUN).
If a phase inside the unit faults or locks up, the unit remains marked as occupied (OCC_RUN = 1). As long as equipment allocation remains locked, BatchCC strictly prohibits closing or deleting the control recipe to prevent leaving unmonitored equipment running autonomously in the plant.

Step-by-Step Implementation Procedure

Identify the Blocked Phase in BatchCC and WinCC:
* In BatchCC, open the Control Recipe view for the hanging batch.
* Expand the recipe hierarchy (Unit Procedure -> Operation -> Phase) and identify the specific Recipe Phase highlighted in yellow (Holding/Holding error) or flashing (Aborting).
* Note the Unit name and the specific technological SFC instance name.
Clear Manual / Stuck Condition on the SFC Phase:
* In WinCC Runtime, navigate to the technological unit graphic screen.
* Click on the block icon for the stuck phase to open its SFC faceplate.
* Check the operating mode: if the SFC is in 'Manual' (MAN), switch it back to 'Automatic' (AUTO).
* If the SFC is in an error state or held on an unsatisfied transition, click the command button 'Abort' (ABORT) or 'Stop' (STOP) directly on the SFC faceplate.
* Once the SFC completes its abort sequence and reaches 'Aborted', click 'Reset' to return the SFC to 'Ready' / 'Idle'.
Emergency Equipment Release via UNIT_PLC Interface:
* If the phase faceplate is completely unresponsive due to a broken communication link or internal SFC defect, open the CFC chart containing the UNIT_PLC block (FB266).
* Open the technological Unit faceplate in WinCC or view the block in CFC test mode.
* Verify block parameters BA_ID, BA_NA, and OCC_RUN.
* Issue a manual equipment reset/release command to UNIT_PLC (or clear the phase allocation bits) to force OCC_RUN to FALSE (0).
Abort and Close Control Recipe in BatchCC:
* Return to BatchCC on the Batch Client station.
* With the SFC phases in 'Aborted' or 'Ready' state and the unit released, right-click the control recipe and select 'Abort'.
* The recipe status transitions from 'Aborting' to 'Aborted'.
* Right-click the control recipe again and select 'Close Control Recipe'. The recipe status transitions to 'Closed'.
Delete the Control Recipe:
* In BatchCC, select the closed batch order.
* Select Edit -> Delete Batch, or right-click and choose 'Delete'.
* Confirm the deletion dialog. The control recipe is permanently removed from the active batch list.

Verification

Verify Successful Recipe Deletion and State Restoration:
1. In BatchCC, confirm that the control recipe status displays 'Aborted', then 'Closed', and finally disappears from the active 'Batches' directory upon deletion.
2. In WinCC Runtime, verify that the Unit graphic overview indicates the unit is 'Free' / 'Available' and no longer displays the previous Batch ID.
3. In CFC test mode on UNIT_PLC (FB266), confirm that output pin OCC_RUN is 0 and BA_ID is 0.
4. Verify that the underlying SFC Type faceplate shows state 'Ready' with operating mode 'AUTO'.

Limitations and Operational Precautions

Operational Precautions and Process Safety Constraints:
- Never force a unit release or abort an SFC phase while field actuators (such as chemical dosing pumps, steam valves, or reactor agitators) are actively energized without first verifying plant safety conditions.
- Bypassing SFC phase logic via direct UNIT_PLC manipulation leaves active field equipment in its last uncommanded state; always ensure manual emergency stop procedures are followed if process hazards exist.
- In validated pharmaceutical or regulated chemical environments (21 CFR Part 11 / GMP), all manual aborts and batch terminations generate mandatory audit trail events that must be justified with operator electronic signatures.

Engineer FAQ

Why does BatchCC refuse to abort a recipe when an SFC is in Manual mode?

In Manual mode, the operator has assumed direct local control over the equipment. To protect plant personnel and prevent equipment damage, the AS blocks supervisory automation systems (including SIMATIC BATCH) from overriding manual commands until the SFC is returned to Automatic.

What is the function of the UNIT_PLC block (FB266) in SIMATIC BATCH?

UNIT_PLC coordinates unit allocation, recipe arbitration, and batch lifecycle tracking between SIMATIC BATCH and the automation controller. It maintains Batch ID, batch status, and equipment occupancy flags (OCC_RUN).

Can I delete an active control recipe while it is in the 'Running' state?

No. By product design, SIMATIC BATCH strictly requires a control recipe to reach a terminal state (Completed, Aborted, or Terminated) and subsequently be 'Closed' before deletion is permitted.

What happens if an SFC phase is aborted from its faceplate but BatchCC does not update?

This indicates a communication failure or message queue backlog between the OS Server (WinCC) and the Batch Server. Verify that the SIMATIC BATCH communication service (Batch Control Server) is running and that WinCC Tag Logging/Alarm Logging channels are active.

Where are deleted batches archived in SIMATIC BATCH?

If the batch archive system is configured, batch execution data is preserved in the SIMATIC BATCH archive database (BATCH_CDV) or exported as an electronic batch record (XML/PDF) prior to removal from the active database.