HuaBook is a technical reference for anyone who works with Huawei SUN2000 solar inverters — whether you own a system, service one, or build software on top of one. It gives you the vocabulary, data structures, and diagnostic strategies you need to understand what your inverter is doing and why.Documentation Index
Fetch the complete documentation index at: https://fop-50527c4b.mintlify.app/llms.txt
Use this file to discover all available pages before exploring further.
Who this reference is for
HuaBook is written for three groups of readers:- Solar system owners who want to understand how well their investment is performing and how to protect their equipment from early failure.
- Technical specialists who need precise offsets, register addresses, and binary structures to build integrations or diagnose faults.
- O&M teams who need a methodical framework for professional maintenance visits, predictive servicing, and dispute resolution.
What HuaBook covers
This reference documents four main areas of the SUN2000 platform:- EMAP log files — the inverter’s internal binary log format, including every log group from daily history records to oscillography captures.
- Modbus registers — real-time data registers for DC input, AC output, energy totals, internal temperatures, and ESS battery state.
- FC 0x41 protocol — Huawei’s proprietary Modbus extension that lets you retrieve multi-megabyte log files from the inverter’s flash storage over a standard Modbus connection.
- O&M strategies — how to use logs for predictive maintenance, efficiency analysis, and generating evidence for warranty or grid-quality disputes.
The ARM + DSP architecture
Every SUN2000 inverter runs a dual-processor design that Huawei describes as “Brain + Heart”:- ARM processor (the brain) handles high-level logic: the EMAP file system, Modbus and network communication stacks, alarm aggregation, and the FC 0x41 file-export engine. The ARM processor is what creates
run_log,alarmg_history, and all other log files you retrieve. - DSP processor (the heart) handles real-time power control: PWM switching, short-circuit protection, overvoltage cutoff, and arc detection — all at millisecond speed. The DSP generates oscillography captures (
dsp_wave_data) and frequency-domain data (dsp_freq_data).
alarmg_history, the ARM recorded it. When you analyze the waveform shape just before that fault, you’re looking at DSP data. Knowing which processor produced a log tells you whether you’re investigating a system-level event or a power-electronics event.
Why EMAP instead of plain text
Most log files on the SUN2000 have the.emap extension. EMAP is Huawei’s proprietary binary log format — the official expansion of the acronym is not publicly documented, but the format itself is consistent across the SUN2000 line.
The inverter uses binary logs rather than plain text for two reasons: size and speed. A text representation of the same data takes 5–10× more storage space, and writing formatted text requires CPU time that the ARM processor may not have during a fault event. EMAP lets the ARM dump raw memory structures directly to flash storage, so log commits are fast and atomic — a power loss mid-write will not corrupt an existing .emap file.
The inverter uses a circular (FIFO) buffer to manage its flash storage. When storage fills up, the oldest log blocks are overwritten first. If you need to investigate a specific event, retrieve logs within 30–90 days of the event — after that, the data may be permanently overwritten.
Navigate HuaBook
Log Files Overview
Learn about every EMAP log group — from daily history records to capacitor health files — and when to use each one.
Modbus Register Map
Browse real-time registers for DC input, AC output, energy totals, and ESS battery state, with type and gain values.
Preventive Maintenance
Use logs to replace fans and capacitors before they fail, find underperforming strings, and build a defensible maintenance record.
Error Code Reference
Look up fault codes by number, with causes and recommended actions for the most common SUN2000 alarms.