OPC-HDA Filtering Examples

Suppose you have the following tags (no hierarchy)

OPC-HDA Tags

CODE

Area A_Temperature
Area A_Compressor Power
Area B_Temperature
Area B_Compressor Power
Max Power

Only include tags prefixed "Area "

CODE

Include "Area *"

Resulting tags

CODE

$body

Only include tags prefixed with "Area " but not tags that include "Temp"

CODE

Include "Area *"
Exclude "*Temp*"

Resulting tags

CODE

Area A_Compressor Power
Area B_Compressor Power

Broadly exclude tags containing "Power", but make exceptions for certain tags

CODE

Exclude "*Power*"
Include "Max Power"

Resulting tags

CODE

$body

Exclude multiple patterns

CODE

Exclude "Area B_*"
Exclude "Area A_*"

Resulting tags

CODE

$body

Suppose you have the following tags (in a hierarchy)

OPC-HDA Tags

CODE

Cooling Tower
  Area A
    Compressor Power
    Wet Bulb
    Temperature
  Area B
    Compressor Power
    Wet Bulb
    Temperature
Max Power

Exclude tags containing "Power"

CODE

Exclude "**/*Power*"

Resulting tags

CODE

$body

Only include tags in Cooling Tower, but exclude tags containing "Bulb"

CODE

Include "Cooling Tower"
Include "Cooling Tower/**"
Exclude "**/*Bulb*"

Resulting tags

CODE

$body

Include only Area A

CODE

Include "Cooling Tower"
Include "Cooling Tower/Area A"
Include "Cooling Tower/Area A/**"

Resulting tags

CODE

$body

Important Note

The filters are tested at each level of the hierarchy, so with a tag like Cooling Tower/Area A/Temperature then Cooling Tower, Cooling Tower/Area A , and Cooling Tower/Area A/Temperature are all evaluated individually. This can help reduce requests to the OPC-HDA historian when using Exclude filters to exclude a node with many nested children, but when using Include filters all parts of the hierarchy you want to include must be explicitly included. For example, in the above example where we only want to include tags from Area A it isn't sufficient to use just Include Cooling Tower/Area A/** because that would not match Cooling Tower or Cooling Tower/Area A.