National Instruments BridgeVIEW 用户手册
Appendix A
HMI Function Reference
A-24
© National Instruments Corporation
Get Historical Trend Info
Use the Get Historical Trend Info VI to obtain the first and last timestamp available in the
historical database for a given tag, and the type of the tag, whether analog or discrete.
historical database for a given tag, and the type of the tag, whether analog or discrete.
Citadel path in is the path to the directory containing the Citadel historical
database. If this path is empty, the VI attempts to use the historical data
directory configured in the active
database. If this path is empty, the VI attempts to use the historical data
directory configured in the active
.scf
file. If this has not been configured,
the VI prompts you to select a data directory.
tag name is the tag about which you want to obtain historical trend
information.
information.
error in (no error) is a cluster that describes the error status before this VI
executes. For more information about this control, see the section
executes. For more information about this control, see the section
in this appendix.
data type is the type of tag, whether discrete, analog, or bit array.
Citadel path out is the path to the directory containing historical data files.
first timestamp is the date and time associated with the first value logged
in the database for this tag.
in the database for this tag.
last timestamp is the date and time associated with the last value logged in
the database for this tag.
the database for this tag.
error out is a cluster that describes the error status after this VI executes.
For more information about this indicator, see the section
For more information about this indicator, see the section
in this appendix.