National Instruments BridgeVIEW 用户手册
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6
Historical Data Logging
and Extraction
This chapter explains the concept of a trend, how to log and extract
historical data, and how to use the Historical Trend Viewer (HTV), a utility
that displays historical data that has been logged to disk with BridgeVIEW.
historical data, and how to use the Historical Trend Viewer (HTV), a utility
that displays historical data that has been logged to disk with BridgeVIEW.
What Is a Trend?
A trend is a display of tag values against time. BridgeVIEW displays tag
values with two types of trends: real-time trends and historical trends. You
can find these trends in the Controls palette.
values with two types of trends: real-time trends and historical trends. You
can find these trends in the Controls palette.
Real-Time Trend
A real-time trend is a display of tag values as they are collected in real time
over a relatively short period of time. You can display a real-time trend in
your HMI by using the Trend Tags VI in the Tags palette in the block
diagram. You also can use the HMI G Wizard to create a real-time trend.
For more information about the HMI G Wizard, see Chapter 4,
over a relatively short period of time. You can display a real-time trend in
your HMI by using the Trend Tags VI in the Tags palette in the block
diagram. You also can use the HMI G Wizard to create a real-time trend.
For more information about the HMI G Wizard, see Chapter 4,
.
Historical Trend
A historical trend is a display of tag values that have been logged to disk.
This is usually over a relatively long period of time. You can display a
historical trend in your HMI by using the Get Historical Tag List VI and
Read Historical Trend VI from the Historical Data palette from the block
diagram. You also can view historical data by launching the HTV utility.
You can use the HMI G Wizard to create a historical trend display.
This is usually over a relatively long period of time. You can display a
historical trend in your HMI by using the Get Historical Tag List VI and
Read Historical Trend VI from the Historical Data palette from the block
diagram. You also can view historical data by launching the HTV utility.
You can use the HMI G Wizard to create a historical trend display.
What Is Citadel?
Citadel is a high performance historical database. With Citadel,
BridgeVIEW can log tags while continually servicing data queries.
BridgeVIEW also includes the Citadel ODBC driver that has special
commands to perform data transforms, making it easy for you to retrieve,
BridgeVIEW can log tags while continually servicing data queries.
BridgeVIEW also includes the Citadel ODBC driver that has special
commands to perform data transforms, making it easy for you to retrieve,