Batch Command Life Cycle

Command and State Life Cycle

The strategic use of standardized command and state lists is a cornerstone of the ISA-88 model, providing a common language for batch control. While human-readable string values are useful for operators and engineers, using their numeric equivalents (Command_Number and State_Number) is significantly more efficient and reliable for PLC logic. This approach simplifies programming by allowing the PLC to handle simple integer comparisons rather than complex and error-prone string processing.

• Batch Execution Modes
• State Transition Diagram
• State Definitions in Tabular Form
• Permissive Start
• Handshake Relationship between Batch Engine and PLC

Batch Execution Modes

When in Auto Mode, the batch engine sets the commands without operator input. When in Manual Mode, the operator can set the commands.

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State Transition Diagram

Command Name	Command Number		State Name	State Number
Start			Idle
Pause			Running
Resume			Complete
Hold			Restarting
Restart			Resetting
Stop			Pausing
Reset			Paused
Abort			Holding
			Held
			Stopping
			Stopped
			Aborting
			Aborted

State Definitions in Tabular Form

Permissive Start

Permissive Start is a functionality that applies to PLI state handling for Equipment, Synchronize, Transfer In, and Transfer Out phases. Its primary purpose is to allow field equipment (PLC) to prevent a phase from starting until specific conditions are met, such as closing an open door.

See Permissive Start for more information.

Start to Complete	See Start to Complete | Batch Command-State Sequence
Pause	See Pause Command| Batch Command-State Sequence
Hold	See Hold Command| Batch Command-State Sequence
Stop	See Stop Command | Batch Command-State Sequence
Abort	See Abort Command| Batch Command-State Sequence
Production Module Restart during Batch Run	See Production Module Restart during Batch Run

Handshake Relationship between Batch Engine and PLC