Esphome M30 Modbus Register 332: m30 3 period

Technical Definition

The register m30 3 period at address 332 is used to monitor m30 3 period on the Esphome M30.

• 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 m30_3_period (Address: 332)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=332, 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: "m30_3_period"
  address: 332
  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[Esphome M30]

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

💡 Engineer's Insight

Analysis: m30 3 period refers to the cycle time or period for a specific measurement or process. Units: Milliseconds or seconds. Used for timing critical operations.

Troubleshooting: An unexpected zero or excessively long period could indicate a sensor failure, communication issue, or a stalled process.