Modbus Esp8266 Modbus Register 105: Hp TW out Leaving Water Temperature

Technical Definition

The register hp TW out Leaving Water Temperature at address 105 is used to monitor hp tw out leaving water Temperature on the Modbus Esp8266.

• Protocol: Modbus RTU
• Data Type: S WORD
• Unit: °C
• 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 hp_TW_out_Leaving_Water_Temperature (Address: 105)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=105, 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: "hp_TW_out_Leaving_Water_Temperature"
  address: 105
  value_type: S_WORD
  unit_of_measurement: "°C"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Modbus Esp8266]

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

💡 Engineer's Insight

Analysis: Leaving water Temperature for heat pump (TW outlet). Units typically in °C or °F. Measures the Temperature of water after it leaves the heat exchanger.

Troubleshooting: Suggests potential issues with heat exchanger performance, refrigerant charge, or pump operation. Check heat transfer and flow rates.