Modbus Esp8266 Modbus Register 122: Hp compressor runnning time

Technical Definition

The register hp compressor runnning time at address 122 is used to monitor hp compressor runnning time on the Modbus Esp8266.

• Protocol: Modbus RTU
• Data Type: U WORD
• Unit: h
• 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_compressor_runnning_time (Address: 122)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=122, 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_compressor_runnning_time"
  address: 122
  value_type: U_WORD
  unit_of_measurement: "h"

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: Compressor running time. Units typically in hours. Tracks the accumulated operational time of the compressor.

Troubleshooting: A zero reading could mean the compressor isn't running, or the counter has reset. Check compressor operation and system demand.