Niagara History Import properties

Figure 104. Edit dialog for Niagara HistoryImport descriptor

Properties of Niagara History Import descriptors available in the Edit or Add dialog are as follows:

Name

Name for the history import descriptor component. If discovered, typically left at default.
Editing name does not affect name of the resulting history (imported into station).
History Id

This property specifies the history name in the local station’s history space, using two parts: “/<stationName>” and “/<historyName>”. If learned, station name is “^” (see note below) and history name reflects the source history name. Typically, you leave both fields at default values, or edit the second (<historyName>) field only.
The “^” character is basically a shorthand character to refer to the device name of the parent container (NiagaraStation component). This may be useful if you have multiple JACEs with histories named the same. You can create and configure a single History Import Descriptor and then duplicate and paste it under the other stations without having to go in and change the station name each time.Note for a Niagara System History Import descriptor, the History Id property is not applicable.
Execution Time

Either Daily (default), Interval, or Manual. If Manual, properties below are not available:
- Time of Day (Daily)
  
  Configurable to any daily time. Default is 2:00am.
- Randomization (Daily)
  
  When the next execution time calculates, a random amount of time between zero milliseconds and this interval is added to the Time of Day. May prevent “server flood” issues if too many history archives are executed at the same time. Default is zero (no randomization).
- Days of Week (Daily and Interval)
  
  Select (check) days of week for archive execution. Default is all days of week.
- Interval (Interval)
  
  Specifies repeating interval for archive execution. Default is every 15 minutes.
- Time of Day (Interval)
  
  Specifies start and end times for interval. Default is 24-hours (start 12:00am, end 11:59pm).
Enabled

Default is true. If set to false, does not execute import of history data.
Capacity

Specifies local storage capacity for imported history, either as Unlimited or Record Count.

If set to Record Count, the following property is available:
- records
  
  Number of records (samples) to locally store. Default is 500.
Full Policy

Either Roll (default) or Stop. Applies only if capacity is set to record count
- If Roll, upon record count, oldest records become overwritten by newest records.
- If Stop, upon record count, importing stops (until history records are locally deleted).
On Demand Poll Enabled

Either true (default) or false. See the next section On demand properties in history import descriptors for more details on this property and the related poll frequency property.
On Demand Poll Frequency

Either “Fast”, “Normal”, or “Slow”.
System Tag Patterns

Specifies one or more text strings matched against text values in “System Tags” properties of remote history extensions, where matching text patterns result in histories imported into the local history space. For more details, see Using System Tags to import Niagara histories.