IIoT, SCADA & Edge Connectivity worked example

OPC UA Tag Coverage at 65% opc ua tag coverage target: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop opc ua tag coverage target to 65%, then walk the calculation through step by step. Estimate the share of process tags exposed through OPC UA from the count of tags published by OPC UA servers against the total tags identified in the tag dictionary, against the program coverage target.

The inputs for this scenario

  • Tags published through OPC UA: 3,200 tags (held at the documented default)
  • Total tags in the in-scope tag dictionary: 4,000 tags (held at the documented default)
  • OPC UA tag coverage target: 65 % (the input this scenario stresses; the baseline uses 90)

Working through the calculation

  • The calculation starts from the formula this tool documents: OPC UA tag coverage = tags published ÷ total in-scope tags × 100.
  • OPC UA tag coverage works out to 80 % at these inputs, and this is the headline figure for the scenario.
  • Coverage gap to target works out to -15 points at these inputs.
  • Tags published through OPC UA works out to 3,200 count at these inputs.
  • Total in-scope tags works out to 4,000 count at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where opc ua tag coverage target sits at 90% and the headline result is 80 %, this scenario lands almost exactly on the baseline at 80 %.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to opc ua tag coverage target, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It measures whether tags are published, not whether they are correctly named, scaled, typed, or updating at the right rate.

Results at a glance

  • OPC UA tag coverage: 80 % (headline result)
  • Coverage gap to target: -15 points
  • Tags published through OPC UA: 3,200 count
  • Total in-scope tags: 4,000 count

Run it with your numbers

  • To rerun this with your own numbers, open the live OPC UA Tag Coverage calculator, set opc ua tag coverage target to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.