Heatpump Modbus Register 195: EXV2 Expansion Valve Openness

Technical Definition

The register EXV2 Expansion Valve Openness at address 195 is used to monitor exv2 expansion valve openness on the heatpump.

• Protocol: Modbus RTU
• Data Type: U WORD
• Unit: P
• 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 EXV2 Expansion Valve Openness (Address: 195)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=195, 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: "EXV2 Expansion Valve Openness"
  address: 195
  value_type: U_WORD
  unit_of_measurement: "P"

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: Represents the opening percentage of the EXV2 expansion valve, typically in %. Indicates precise refrigerant flow control.

Troubleshooting: A zero value might indicate a closed valve, a sensor fault, or a control system issue preventing opening.