Heatpump Modbus Register 111: Entity prefix System Total Water Outlet Temperature T1B

Technical Definition

The register entity prefix System Total Water Outlet Temperature T1B at address 111 is used to monitor entity prefix system total water outlet Temperature t1b on the heatpump.

• 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 entity_prefix System Total Water Outlet Temperature T1B (Address: 111)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=111, 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: "entity_prefix System Total Water Outlet Temperature T1B"
  address: 111
  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[heatpump]

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

💡 Engineer's Insight

Analysis: System total water outlet Temperature (T1B) in degrees Celsius. Indicates heat delivered to the system.

Troubleshooting: Check pump operation, heat exchanger, and thermostat settings if reading is unexpectedly low or zero.