IIoT, SCADA & Edge Connectivity worked example

PLC Connectivity Backlog at 57% testing and operations validation allowance: a worked example

Push testing and operations validation allowance up to 57% and the picture changes. This example computes every intermediate figure at that operating point. Use it when an OT integration lead is sizing the engineering team needed to clear a backlog of PLCs not yet exposed to OPC UA, MQTT, or the historian.

The inputs for this scenario

  • PLCs awaiting network connectivity: 42 PLCs (unchanged)
  • Engineer PLC connectivity throughput: 0.5 PLCs / hr (unchanged)
  • Testing and operations validation allowance: 57 % (raised for this scenario; the documented default is 50)

Working through the calculation

  • Applying the documented formula (Base PLC connectivity hours = PLC count รท engineer rate) to the inputs above produces each figure below.
  • At this operating point the engine returns 132 hr for required plc connectivity hours, the number this scenario is built around.
  • At this operating point the engine returns 84 hr for base plc connectivity hours.
  • At this operating point the engine returns 57 % for testing and validation allowance.
  • At this operating point the engine returns 0.5 pieces / min for engineer connectivity rate.

How this compares with the baseline

  • Against the tool's baseline example, where testing and operations validation allowance sits at 50% and the headline result is 126 hr, this scenario comes in 4.67% above the baseline at 132 hr.
  • It computes total PLC connectivity engineering hours by dividing the backlog count by the engineer's connectivity rate, then inflating base hours by the testing and operations-validation allowance. 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

  • Required PLC connectivity hours: 132 hr (headline result)
  • Base PLC connectivity hours: 84 hr
  • Testing and validation allowance: 57 %
  • Engineer connectivity rate: 0.5 pieces / min

Run it with your numbers

  • Every input above is editable in the live PLC Connectivity Backlog calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.