Replay Instructions¶

Replay instructions allow you to rerun scheduling tasks from a specific point in time - effectively “rewinding the clock” to reprocess historical data.

You can configure a replay by selecting a replay instruction when setting up either a single instruction or an instruction sequence.

The following are available replay instructions:

Service	Instruction	Description
AlarmEventService	`ScanAlarmByRange` (Event Replay - Run Once)	Scans a specific Alarm/Event over a defined date range. (Available for Single Instruction or Non-Recurring Instruction Sequence)
AlarmEventService	`ScanEventGroupByRange` (Event Group Replay - Run Once)	Scans a specific Event Group over a defined date range. (Available for Single Instruction or Non-Recurring Instruction Sequence)
CalcEngineService	`Calculation Group Replay`	Scans a specific Calculation Group over a defined date range. (Available for Single Instruction or Non-Recurring Instruction Sequence)
DataService	`ScanAggregateGroupByRange` (Aggregate Group Replay)	Scans a specific Aggregate Group over a defined date range. (Available for Single Instruction or Non-Recurring Instruction Sequence)
DataService	`Simple Historize Group by Range`	Performs simple historization of the last value of all input tags into output tags at a specified frequency. If frequency is not set or is 0, a default of 1 minute is used.
ExternalDataService	`InstructDataConnectorReadHistorical`	Instructs a data connector to read historical values
ExternalDataService	`InstructDataConnectorWriteHistorical`	Instructs a data connector to write historical values

When configuring a replay instruction, you must define a time range using one of the following options:

Absolute - Specify both a start and end time.
Relative - The start time is optional. If omitted, the system time at execution will be used. You can also use a negative value in Seconds From Start Time to go backwards in time.

Note

When choosing the Absolute option, the value in the End Time field is ignored for the AlarmEventService, CalcEngineService and DataService-AggregateGroup instructions. Replays always process data up to the current system time, regardless of the end time specified.