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
• Batch Commands and States Reference Table
• State Definitions in Tabular Form
• Permissive Start
• Handshake Relationship between Batch Engine and PLC

In 3.81.13 SP0 and later: When phases (including Unit Procedures and Operations) are in the Stopped state, they do not respond to commands issued to them such as Pause, Resume, Hold, or Restart, because they are not active phases. In MES 3.81.13 SP3, MES 4.83.3 SP3, and later: Abort is the exception. A Stopped step, including an equipment phase, a Unit Procedure, or an Operation, can be aborted. The step goes from Stopped to Aborting, then to Aborted. The parent batch is not aborted, and later steps still run. The electronic batch record shows Aborted as that step's terminal state.

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

Batch Commands and States Reference Table

Command Name	Command Number	State Name	State Number
NONE	0	IDLE	1
START	1	RUNNING	2
PAUSE	2	COMPLETE	3
RESUME	3	RESTARTING	4
HOLD	4	RESETTING	5
RESTART	5	PAUSING	6
STOP	6	PAUSED	7
RESET	7	HOLDING	8
ABORT	8	HELD	9
—	—	STOPPING	10
—	—	STOPPED	11
—	—	ABORTING	12
—	—	ABORTED	13
—	—	PERMISSIVE START	17

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Key Execution Details

• Commands (Numbers 0–8) are issued by the batch engine to request state changes in the PLC.
• States (Numbers 1–13, and 17) are written by the PLC back to the batch engine to report current equipment phase execution.
• Permissive Start (State 17) serves as a pre-idle condition outside the procedure boundary, enabling PLC safety verification before transitioning to Idle without requiring a command number.

State Definitions in Tabular Form

Current State	Start (1)	Stop (6)	Hold (4)	Restart (5)	Abort (8)	Reset (7)	Pause (2)	Resume (3)	Automatic Next State (No Command)
Permissive Start (17)	—	—	—	—	—	—	—	—	Idle
Idle (1)	Running	—	—	—	—	—	—	—	—
Running (2)	—	Stopping	Holding	—	Aborting	—	Pausing	—	Complete
Complete (3)	—	—	—	—	—	Resetting	—	—	—
Pausing (6)	—	Stopping	Holding	—	Aborting	—	—	—	Paused
Paused (7)	—	Stopping	Holding	—	Aborting	—	—	Running	—
Holding (8)	—	Stopping	—	—	Aborting	—	—	—	Held
Held (9)	—	Stopping	—	Restarting	Aborting	—	—	—	—
Restarting (4)	—	Stopping	Holding	—	Aborting	—	—	—	Running
Stopping (10)	—	—	—	—	Aborting	—	—	—	Stopped
Stopped (11)	—	—	—	—	Aborting	Resetting	—	—	—
Aborting (12)	—	—	—	—	—	—	—	—	Aborted
Aborted (13)	—	—	—	—	—	Resetting	—	—	—
Resetting (5)	—	—	—	—

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 In 3.81.13 SP0 and later: When phases (including Unit Procedures and Operations) are in the Stopped state, they do not respond to commands issued to them such as Pause, Resume, Hold, Restart, etc. because they are not active phases.
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