Lockout Tagout Sequence Calculator

A lockout tagout sequence calculator reviews the entered record of an energy-control sequence. Its primary result is the Sequence comparison, supported by counts for Total steps, Complete steps, Missing steps, Unknown steps, Order errors, and Duplicate energy sources.

This record review is used during preparation, documentation checks, and internal procedure review for equipment shutdown and energy isolation. It helps identify whether the documented sequence is internally complete and arranged in the expected step order before a qualified person performs the actual field procedure.

The calculator does not size conductors, determine ampacity, evaluate voltage drop, verify feeder loading, or calculate raceway fill. Its electrical purpose is procedural: organizing documented steps associated with identified energy sources and flagging entered record conditions that need correction.

Sequence Step Records

Each entered row represents one documented step in the lockout tagout sequence.

Field	Use in the sequence review
Step ID	Identifies the documented sequence record.
Step order (step)	States the intended position of that record in the sequence.
Step state	Records whether the step is Complete, Missing, or otherwise unresolved.
Energy source ID	Identifies the energy source associated with the sequence record.
Required step	Indicates whether the documented record is required for the entered sequence.

The worksheet evaluates the relationship between row position and Step order (step). A row entered first should have a step order of 1, the second row should have a step order of 2, and so on. A mismatch is reported as an order error.

The Energy source ID field is also reviewed for repeated identifiers. Repeated IDs may indicate that the same source was entered more than once, or that the sequence documentation needs clarification. The calculator identifies the duplication but does not determine whether repeated control actions are appropriate for a particular machine or system.

Calculation Results

The calculator produces these record counts:

• Total steps: Number of entered rows.
• Complete steps: Number of rows with Step state set to Complete.
• Missing steps: Number of rows with Step state set to Missing.
• Unknown steps: Number of rows with an unresolved or unknown entered status.
• Order errors: Number of rows where Step order (step) does not match the row’s position.
• Duplicate energy sources: Number of repeated Energy source ID entries.
• Sequence comparison: Entered complete only when no missing, unknown, order-error, or duplicate counts remain.

The output is an entered-record condition, not a determination that equipment is de-energized or safe to service.

Formula Basis

The worksheet uses count-based checks:

\(\displaystyle \text{complete steps} = \operatorname{count}(\text{rows with Step state = Complete})\)

\(\displaystyle \text{missing steps} = \operatorname{count}(\text{rows with Step state = Missing})\)

\(\displaystyle \text{order errors} = \operatorname{count}(\text{rows where Step order differs from row position})\)

The Sequence comparison is Entered complete only when all of the following counts are zero:

\(\displaystyle \text{Missing steps} = \text{Unknown steps} = \text{Order errors} = \text{Duplicate energy sources} = 0\)

A sequence can therefore show every entered step as Complete while still failing the entered-complete condition because a step is out of order or an Energy source ID is duplicated.

Calculation Example

A documented record contains one row:

Field	Entered value
Step ID	1
Step order (step)	1
Step state	Complete
Energy source ID	Required step
Required step	Yes

The calculated result is:

Result	Value
Total steps	1 rows
Complete steps	1 rows
Missing steps	0 rows
Unknown steps	0 rows
Order errors	0 rows
Duplicate energy sources	0 rows
Sequence comparison	Entered complete

The status is Entered complete because the single row is marked Complete, its Step order (step) matches its first-row position, and no repeated Energy source ID is present.

If a second row were added but assigned Step order (step) 1 instead of 2, the worksheet would report an Order error. If that second row repeated an existing Energy source ID, it would also produce a Duplicate energy sources result. Either condition prevents the sequence from being classified as Entered complete.

Field Verification and Energy Control

An entered-complete result does not verify electrical isolation, mechanical isolation, stored-energy release, absence of voltage, or completion of a lockout tagout procedure.

Field work still requires the applicable energy-control procedure, equipment-specific instructions, qualified-person practices where electrical hazards are present, appropriate test instruments, and the governing employer requirements and AHJ requirements. Electrical verification must address the actual equipment and all applicable sources of energy, including possible backfeed, stored electrical energy, and other hazardous energy conditions identified in the field.

The calculator’s boundary is the sequence screen only: it checks entered step states, sequence order, and repeated Energy source ID records. It does not establish a zero-energy state or make an energy-control conclusion.