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Light Modbus Register 1200: Cooling set Temperature

Technical documentation for Modbus register 1200 on Light. Data type: INT16. Includes Python and YAML configuration examples.

January 16, 2026 1 min read

Technical Definition

The register Cooling set Temperature at address 1200 is used to monitor cooling set Temperature on the Light.

  • Protocol: Modbus RTU
  • Data Type: INT16
  • 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 Cooling set temperature (Address: 1200)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=1200, 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: "Cooling set temperature"
  address: 1200
  value_type: INT16
  unit_of_measurement: "°C"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Light]

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


💡 Engineer's Insight

Analysis: Target Temperature for the cooling system. Units: Degrees Celsius (°C) or Fahrenheit (°F).

Troubleshooting: Incorrect setpoint. Verify the desired Temperature is programmed correctly. Check for unintended manual adjustments.