DTC Detection Debugging Guide¶

What to Look For in Home Assistant Logs¶

After reducing log verbosity, the DTC detection process is now clearly visible with these markers:

✅ Success Path¶

INFO - Starting automatic inverter type detection
INFO - ✓ DTC Detection - Read DTC code: 5400 from holding register 30000
INFO - ✓ DTC Detection - Matched DTC code 5400 to profile 'mod_6000_15000tl3_xh'
INFO - ✓ Auto-detected from DTC code 5400: MOD 6000-15000TL3-XH

⚠️ Failure Indicators¶

DTC Read Failed:

INFO - Starting automatic inverter type detection
WARNING - Failed to read DTC code from register 30000: [error details]
INFO - DTC and model name detection failed, trying register-based detection...

DTC Returns Zero:

INFO - Starting automatic inverter type detection
WARNING - DTC code register 30000 returned 0 or invalid value: 0
INFO - DTC and model name detection failed, trying register-based detection...

Unknown DTC Code:

INFO - ✓ DTC Detection - Read DTC code: 9999 from holding register 30000
WARNING - ✗ DTC Detection - Unknown DTC code: 9999 (not in supported models)
INFO - DTC and model name detection failed, trying register-based detection...

Valid DTC Codes¶

DTC Code	Model Series	Profile	Notes
3501	SPH 3000-6000TL BL (legacy)	sph_3000_6000	Pre-UP model, uses legacy profile
3502	SPH 3000-6000TL BL -UP	sph_3000_6000_v201	Upgraded model with V2.01
3601	SPH 4000-10000TL3 BH-UP	sph_tl3_3000_10000	Three-phase hybrid
5100	MIN 2500-6000TL-XH	min_3000_6000_tl_x	Single-phase hybrid
5200	MIC/MIN 2500-6000TL-X	min_3000_6000_tl_x	Shared code
5201	MIN 7000-10000TL-X	min_7000_10000_tl_x	Three PV strings
5400	MOD-XH/MID-XH	mod_6000_15000tl3_xh	Three-phase, shared code

How to View Logs in Home Assistant¶

Method 1: Via UI¶

Go to Settings → System → Logs
Search for "DTC Detection"
Look for ✓ or ✗ markers

Method 2: Via Log File¶

# View live logs
tail -f /config/home-assistant.log | grep "DTC"

# Search recent logs
grep "DTC Detection" /config/home-assistant.log | tail -20

# Full detection sequence
grep -A 5 "Starting automatic inverter type detection" /config/home-assistant.log | tail -30

Common Issues and Solutions¶

Issue 1: DTC Read Fails Immediately¶

Symptom:

WARNING - Failed to read DTC code from register 30000: [ModbusIOException]

Possible Causes: - Emulator not running or not accessible - Wrong host/port in HA configuration - Firewall blocking connection - Modbus device ID mismatch

Debug Steps:

# Test from HA machine
python3 test_modbus_dtc.py --host <emulator-ip> --port 502

# Check network connectivity
ping <emulator-ip>
telnet <emulator-ip> 502

Issue 2: DTC Returns Zero¶

Symptom:

WARNING - DTC code register 30000 returned 0 or invalid value: 0

Possible Causes: - Emulator profile doesn't define DTC default value - Register 30000 not implemented in holding registers - Reading from wrong register type (input vs holding)

Debug Steps: 1. Check emulator is serving register 30000:

python3 test_dtc_code.py

2. Verify it's a HOLDING register (not input) 3. Check MOD profile has default: 5400 for register 30000

Issue 3: Connection Works in Modbus Poll but Not HA¶

Symptom: - Modbus Poll can read DTC code 5400 - HA logs show "Failed to read DTC code"

Possible Causes: - Device ID mismatch (HA using different ID than Modbus Poll) - Timeout too short in HA - Register address offset issue

Debug Steps: 1. Check device ID in both tools: - Modbus Poll: usually shown in connection settings - HA: check config entry or use device_id=1 2. Increase timeout in HA config 3. Verify register address is exactly 30000 (not 30001 or 29999)

Issue 4: Unknown DTC Code¶

Symptom:

WARNING - ✗ DTC Detection - Unknown DTC code: 5400 (not in supported models)

Possible Causes: - Integration doesn't have 5400 mapped to a profile - Old version of integration

Solution: Check auto_detection.py has this mapping:

dtc_map = {
    ...
    5400: 'mod_6000_15000tl3_xh',  # MOD-XH\MID-XH
    ...
}

Testing DTC Detection¶

Test 1: Verify Emulator Serves DTC¶

python3 test_dtc_code.py

Expected output:

✓ Model loaded: MOD 6000-15000TL3-XH
✓ Simulated value: 5400
✓ CORRECT! DTC code 5400 for MOD series

Test 2: Test Modbus Connection¶

python3 test_modbus_dtc.py --host localhost --port 502

Expected output:

✓ Connected successfully
✓ Valid DTC code: MOD-XH/MID-XH
Value: 5400

Test 3: Watch HA Logs Live¶

# In one terminal - watch logs
tail -f /config/home-assistant.log | grep -E "DTC|auto.*detect"

# In another terminal - reload integration
# (via HA UI: Settings → Integrations → Growatt → Reload)

What Changed¶

Before (Verbose):¶

INFO - Fixed config entry to store register map key: MOD_6000_15000TL3_XH
INFO - Identified register map as: MOD_6000_15000TL3_XH
INFO - Initialized Growatt client with register map: MOD_6000_15000TL3_XH
INFO - Midnight callback registered for daily total resets
INFO - Read serial number: GRW12345678
INFO - Read firmware version: 1.39
INFO - Read inverter type: MOD-15000TL3-XH
INFO - Read protocol version: VPP 2.01
INFO - Detected 3-phase hybrid - SPH TL3 or MOD series
INFO - Detected 31200 range (VPP Protocol) - MOD series

After (Clean):¶

INFO - Starting automatic inverter type detection
INFO - ✓ DTC Detection - Read DTC code: 5400 from holding register 30000
INFO - ✓ DTC Detection - Matched DTC code 5400 to profile 'mod_6000_15000tl3_xh'
INFO - ✓ Auto-detected from DTC code 5400: MOD 6000-15000TL3-XH
INFO - Midnight reset triggered - storing previous day totals

Routine operations are now at DEBUG level - enable debug logging if needed:

logger:
  default: info
  logs:
    custom_components.growatt_modbus: debug