Heatpump Modbus Register 139: Entity prefix Limit Scheme Of Outdoor Unit Current

Technical Definition

The register entity prefix Limit Scheme Of Outdoor Unit Current at address 139 is used to monitor entity prefix limit scheme of outdoor unit current on the heatpump.

• Protocol: Modbus RTU
• Data Type: U WORD
• Unit:
• 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 Limit Scheme Of Outdoor Unit Current (Address: 139)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=139, 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 Limit Scheme Of Outdoor Unit Current"
  address: 139
  value_type: U_WORD
  unit_of_measurement: ""

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: Outdoor Unit Current Limit (Amps). Sets the maximum permissible current for the outdoor unit.

Troubleshooting: Constantly hitting limit implies an overload condition or a faulty compressor/fan motor.