Solis Modbus Inv Modbus Register 3042: Grid frequency

Technical Definition

The register Grid frequency at address 3042 is used to monitor grid frequency on the Solis Modbus Inv.

• Protocol: Modbus RTU
• Data Type: U WORD
• Unit: Hz
• 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 Grid frequency (Address: 3042)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=3042, 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: "Grid frequency"
  address: 3042
  value_type: U_WORD
  unit_of_measurement: "Hz"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Solis Modbus Inv]

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

💡 Engineer's Insight

Analysis: Frequency of the AC grid to which the inverter is connected. Units: Hertz (Hz). Must match grid standard (e.g., 50Hz or 60Hz).

Troubleshooting: Zero or out-of-range values suggest grid loss, incorrect settings, or inverter malfunction. Essential for safe grid synchronization.