ihCollectors Table

The ihCollectors table contains the configuration and status information for each collector connected to the Historian server. Each row in this table represents a collector that is connected to the archiver. The following table describes the columns of the ihCollectors table.

Table 1. ihCollectors Table
Column NameData TypeDescription
CollectorNameVT_BSTRThe name of the collector. The collector name is unique in a specific Historian server.
CollectorDescriptionVT_BSTRThe user description for the collector.
CommentVT_BSTRThe user comment associated with the collector.
ComputerNameVT_BSTRThe name of the Windows computer on which the collector is running.
StatusVT_BSTRThe status of the specified collector:
  • Unknown
  • Starting
  • Running
  • Stopping
  • Stopped
CollectorTypeVT_BSTRThe type of collector responsible for collecting data for the tag:
  • Undefined
  • iFIX
  • Simulation
  • OPC
  • OPC AE
  • File
  • iFIXLabData
  • ManualEntry
  • Simulation
  • Calculation
  • ServerToServer
  • Other
MaximumDiskFreeBufferSizeVT_I4The maximum size (in MB) of the disk buffer for outgoing data.
MaximumMemoryBufferSizeVT_I4The maximum size of the memory buffer (in MB) for outgoing data.

The memory buffer stores data during short-term or momentary interruptions of the server connection. The disk buffer handles long-duration outages.

ShouldAdjustTimeVT_BOOLIf the data source supplies the timestamps, this value is False. If the collector supplies the timestamps, this value is True.
Note: This column does not change collector times to match the server time. It indicates whether an increment of time is added or subtracted to compensate for the relative difference between the server and collector clocks, independent of time zone differences.
ShouldQueueWritesVT_BOOLIndicates whether queue writes are allowed.
CanBrowseSourceVT_BOOLIf True, this column indicates that the collector can browse its source for tags.
CanSourceTimestampVT_BOOLIndicates whether the data source can provide timestamps along with the data.
StatusOutputAddressVT_BSTRAn address or tagname in the data source to output current collector status.
RateOutputAddressVT_BSTRAn address or tagname in the data source into which the collector writes the current value of the events per minute output.
HeartbeatOutputAddressVT_BSTRThe address in the source database into which the collector writes the heartbeat signal output.
CollectorGeneral1VT_BSTRThe general (or spare) configuration fields for the collector. The CollectorGeneral1 column is not user-defined, and is different for each collector.
CollectorGeneral2VT_BSTRThe general (or spare) configuration fields for the collector. The CollectorGeneral2 column is not user-defined, and is different for each collector.
CollectorGeneral3VT_BSTRThe general (or spare) configuration fields for the collector. The CollectorGeneral3 column is not user-defined, and is different for each collector.
CollectorGeneral4VT_BSTRThe general (or spare) configuration fields for the collector. The CollectorGeneral4 column is not user-defined, and is different for each collector.
CollectorGeneral5VT_BSTRThe general (or spare) configuration fields for the collector. The CollectorGeneral5 column is not user-defined, and is different for each collector.
LastModifiedVT_DBTimeStampThe date and time that the collector configuration was last modified. The time structure includes milliseconds.
LastModifiedUserVT_BSTRThe username of the Windows user who last modified the collector configuration.
SourceTimeInLocalTimeVT_BOOLFor data source timestamps only. Indicates whether the timestamps use local time. If the value is False, UTC time is used.
CollectionDelayVT_I4The length of time, in seconds, that the collector should delay collection at startup (to allow the data source time to initialize).
DefaultTagPrefixVT_BSTRThe prefix that is automatically applied to all tagnames added by the specified collector.
DefaultCollectionIntervalVT_I4The collection interval, in milliseconds, for tags added by the collector.
DefaultCollectionTypeVT_BSTRType of collection used to acquire data for tags added by the collector:
  • Unsolicited: The collector accepts data from the source whenever the source presents the data.
  • Polled: The collector acquires data from a source on a periodic schedule determined by the collector.
Note: Not all collectors support unsolicited type collection.
DefaultTimeStampTypeVT_BSTRType of timestamping applied to data samples at collection time for tags added by the collector:
  • Source: The source delivers the timestamp along with the data sample.
  • Collector: The collector delivers the timestamp along with the collected data.
DefaultCollectorCompressionVT_BOOLIndicates whether default collector compression is enabled for tags added by the collector.
DefaultCollectorCompressionDeadbandVT_R4The default collector compression deadband for tags added by the collector.
DefaultCollectorCompressionTimeoutVT_I4The default collector compression timeout value.
DisableOnTheFlyChangesVT_BOOLIndicates whether a user can make on-the-fly changes to this tag. When enabled (True) you can make changes to this tag without having to restart the collector.

When disabled (False), any changes you make to this tag do not affect collection until you restart the collector.

DefaultSpikeLogicVT_BOOLIndicates whether Spike Logic is enabled.
DefaultSpikeMultiplierVT_R4The default Spike Logic multiplier.
DefaultSpikeIntervalVT_I4The default Spike Logic interval.
RedundancyEnabledVT_BOOLIndicates whether collector redundancy is enabled.
PrincipalCollectorVT_BSTRIndicates the primary collector.
IsActiveRedundantCollectorVT_BOOLIndicates whether the current collector is active.
FailoverOnCollectorStatusVT_BOOLIndicates whether the collector is set to fail over on an unknown collector status.
FailoverOnBadQualityVT_BOOLIndicates whether the collector is set to fail over on bad data quality received from the watchdog tag.
FailoverOnValueVT_BOOLIndicates whether the collector is set to fail over on a change in value.
FailoverValueChangeTypeVT_I4The value for the FailoverOnValue option.
WatchdogValueMaxUnchangedPeriodVT_I4The maximum period for an unchanged value.
WatchdogTagNameVT_BSTRThe watchdog tag name.
TimeZoneVT_BSTRThe type of time zone used:
  • Client
  • Server
  • Explicit bias number (number of minutes from GMT)
DaylightSavingTimeVT_BOOLIndicates whether Daylight Saving Time logic should be applied to timestamps.
RowCountVT_I4The maximum number of rows that can be returned. A value of 0 indicates there is no limit to the number of rows returned.

ihCollectors Examples

One task that you might want to perform on the ihCollectors table could be retrieving and recording the state of the collectors when an event happens. Recording conditions when an event happens is useful in troubleshooting.

Sample SQL statements for the ihCollectors table are outlined in the following examples.

Example 1: Retrieve All Collectors With Status Information

SELECT collectorname, collectordescription AS desc, status
FROM ihcollectors

Example 2: Retrieve All Collectors Not Running

SELECT collectorname, collectordescription AS desc, status
FROM ihcollectors WHERE status!=running