Diagnostics for Modbus in Home Assistant custom components—framing/extra-data errors, unit_id mismatches, pacing/timeouts, write contention, and logging patterns.
SKILL.md
Modbus Troubleshooting
Use when Modbus IO misbehaves (timeouts, extra data, wrong values).
Quick checks
Verify device_id/unit_id on every call; wrong unit → timeouts.
Add pacing (message_wait_milliseconds) and avoid immediate post-write polls.
For RTU-over-TCP, flush/reset framer/buffer; reconnect on extra-data.
Log address/unit/function and raw words to spot endian or offset issues.
