Ctc Ecozenith I250 Modbus Register 647: Heat pump 1: Compressor start delay timer

Technical Definition

The register Heat pump 1: Compressor start delay timer at address 647 is used to monitor heat pump 1: compressor start delay timer on the Ctc Ecozenith I250.

• Protocol: Modbus RTU
• Data Type: S 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 Heat pump 1: Compressor start delay timer (Address: 647)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=647, 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: "Heat pump 1: Compressor start delay timer"
  address: 647
  value_type: S_WORD
  unit_of_measurement: ""

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Ctc Ecozenith I250]

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

💡 Engineer's Insight

Analysis: Compressor start delay timer prevents rapid cycling. Units: Seconds or minutes. Protects the compressor motor from premature starts after power interruptions or shutdowns.

Troubleshooting: A consistently active timer (high value) might indicate frequent power cycling or a fault requiring investigation into system controls or power supply stability.