Tags VIs

LabVIEW 2017 Datalogging and Supervisory Control Module Help

Edition Date: March 2017

Part Number: 371618K-01

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Owning Palette: DSC Module VIs and Functions

Requires: DSC Module. This topic might not match its corresponding palette in LabVIEW depending on your operating system, licensed product(s), and target.

Tags are data sources that contain values, traces, alarms, and events of shared variables and I/O server data items. Use the Tags VIs to complete the following tasks programmatically:

  • Read and write multiple shared variables.
  • Read and acknowledge alarms for a process, an alarm area, or multiple shared variables.
  • Configure bindings between front panel controls and shared variables.
  • Read trends for multiple shared variables.
  • Redirect operations to shared variables under different processes or computers.

The VIs and functions on this palette can return general LabVIEW error codes or specific DSC Module error codes.

Palette ObjectDescription
Acknowledge Alarms by Tag NameAcknowledges alarms for a tag. You need to open the tag by using the Open Tag Reader VI before you acknowledge the alarms. Wire data to the tag name input to determine the polymorphic instance to use or manually select the instance.
Close Tag ReaderCloses a Tag Reader instance and releases all resources that LabVIEW allocates to the instance. This VI closes the specified Tag Reader instance regardless of whether an error occurred in a preceding operation.
Get Computer ListReturns an array of computer names on the local network.
Open Tag ReaderCreates new tags for the shared variables and I/O server data items under a root URL. This VI returns a Tag Reader instance that contains all these tags. Use the Tag Reader instance to perform other tag-related operations, such as reading and writing values, accessing historical data, and reading meta information.
Read Current Tag Trace as TrendReads the current trend of a tag in waveform format. You must manually select the polymorphic instance to use.
Read TagReads the value of specified tags. You must manually select the polymorphic instance to use.
Read Tag AlarmsReads alarms for the specified tags, processes, or alarm areas. You must manually select the polymorphic instance to use.
Read Tag TraceReads the historical trace of a tag. You must manually select the polymorphic instance to use.
Redirect Root URLRedirects a Tag Reader instance to a new root URL. This VI allows you to access the tags under this new root URL.
Write TagWrites data to the value of a tag. Use the Read Tag VI to read the value of a tag. Wire data to the data input to determine the polymorphic instance to use or manually select the instance.


SubpaletteDescription
Utility VIsUse the Utility VIs to get information about a Tag Reader instance or to configure front panel bindings.

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