IIoT, SCADA & Edge Connectivity calculator

Machine Connectivity Rate Calculator

Estimate the share of machines actually publishing data right now. Enter the count of machines reporting in the last polling window, the total connectable machines, and the program target. The calculator returns the live connectivity rate and the gap to target.

What this calculator does

  • Estimate the share of plant machines that are publishing live data right now from the count of machines actively reporting against the total connectable machines, against the program target.
  • Use it when an OT manager or plant manager needs a clean live-connectivity number for the morning meeting board, separate from the slower edge gateway deployment view.
  • It returns the share of plant machines actively publishing data in the last polling window and the gap to the operations target.

Formula used

  • Live machine connectivity rate = machines reporting ÷ total connectable machines × 100
  • Connectivity gap to target = target rate - actual rate (negative gap means below target)

Inputs explained

  • Machines reporting live data in the last polling window: Use the count of machines with a fresh tag in the last polling window (typical 30 seconds to 5 minutes for production machines).
  • Total connectable machines: Use the count of PLC, CNC, robot, or HMI assets that should be reporting per the asset register and IIoT rollout scope.
  • Live connectivity target: Use the operations target (mature programs typically run 95 to 99 percent live connectivity; new rollouts may run 70 to 90 percent during shake-out).

How to use the result

  • Use it on the daily operations board, in shift handover, and any time a dashboard goes blank or a key tag stops updating.
  • Live connectivity says nothing about data accuracy. A machine can be reporting a stuck or stale tag while still appearing connected; pair with the OT data completeness calculator for a quality view.

Common questions

  • What polling window should I use? Use whatever the historian or broker uses to declare a tag stale (typical 30 seconds for fast PLC tags, 5 minutes for slow process tags). Match the window to the actual asset class so the rate is meaningful.
  • Why does this differ from edge gateway coverage? Coverage measures which machines have a gateway deployed (slow-changing). Connectivity rate measures which machines are publishing right now (fast-changing). Both are needed.
  • How do I count a machine that publishes one tag but not all of them? Treat it as connected for this calculator. Use the OT data completeness calculator to capture the partial-publish problem at tag level.
  • What target is realistic on a brownfield plant? 95 to 98 percent live connectivity is common after stabilization. Below 90 percent usually points to gateway power, network port, or PLC firmware issues that need a containment plan.

Last reviewed 2026-05-12.