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Deye12 Modbus Register 605: Sun12k-Internal CT L2 Power

Technical documentation for Modbus register 605 on Deye12. Data type: S WORD. Includes Python and YAML configuration examples.

January 16, 2026 3 read

Technical Definition

The register sun12k-Internal CT L2 Power at address 605 is used to monitor sun12k-internal ct l2 power on the Deye12.

  • Protocol: Modbus RTU
  • Data Type: S WORD
  • Unit: W
  • Access: Read Only

How to Read (Python pymodbus)

Use this code snippet to read this specific value via RS485:

from pymodbus.client.sync import ModbusSerialClient

client = ModbusSerialClient(method='rtu', port='/dev/ttyUSB0', baudrate=9600)
client.connect()

# Read sun12k-Internal CT L2 Power (Address: 605)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=605, count=2, unit=1)

if not result.isError():
    print(f"Raw Value: {result.registers}")
else:
    print("Error reading register")

client.close()

Integration (Home Assistant)

Paste this into your configuration.yaml:

- platform: modbus_controller
  name: "sun12k-Internal CT L2 Power"
  address: 605
  value_type: S_WORD
  unit_of_measurement: "W"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Deye12]

    PLC -- "A+ (D+)" --> Device
    PLC -- "B- (D-)" --> Device
    PLC -- GND --> Device


💡 Engineer's Insight

Analysis: Internal CT L2 Power (W). Measures power flow on Phase 2 via internal current transformer. Positive for export, negative for import.

Troubleshooting: Zero may indicate no load/generation on L2, CT failure, or incorrect wiring. Verify connections and active loads/generation.