IIoT, SCADA & Edge Connectivity worked example

OPC UA Tag Coverage at 99% opc ua tag coverage target: a worked example

Push opc ua tag coverage target up to 99% and the picture changes. This example computes every intermediate figure at that operating point. Use it when a controls engineer or integrator is tracking how much of the plant tag dictionary is actually addressable through OPC UA on the way to a unified namespace or MES integration.

The inputs for this scenario

  • Tags published through OPC UA: 3,200 tags (unchanged)
  • Total tags in the in-scope tag dictionary: 4,000 tags (unchanged)
  • OPC UA tag coverage target: 99 % (raised for this scenario; the documented default is 90)

Working through the calculation

  • Applying the documented formula (OPC UA tag coverage = tags published ÷ total in-scope tags × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 80 % for opc ua tag coverage, the number this scenario is built around.
  • At this operating point the engine returns 19 points for coverage gap to target.
  • At this operating point the engine returns 3,200 count for tags published through opc ua.
  • At this operating point the engine returns 4,000 count for total in-scope tags.

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 %.
  • It computes the share of the in-scope tag dictionary published through OPC UA and the point gap to your coverage target. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • OPC UA tag coverage: 80 % (headline result)
  • Coverage gap to target: 19 points
  • Tags published through OPC UA: 3,200 count
  • Total in-scope tags: 4,000 count

Run it with your numbers

  • Every input above is editable in the live OPC UA Tag Coverage calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.