EmsTechLabs Logo EmsTechLabs

Esphome Web 4C96D0 Modbus Register 40096: DC Current

Technical documentation for Modbus register 40096 on Esphome Web 4C96D0. Data type: U WORD. Includes Python and YAML configuration examples.

January 16, 2026 3 read

Technical Definition

The register DC Current at address 40096 is used to monitor dc current on the Esphome Web 4C96D0.

  • Protocol: Modbus RTU
  • Data Type: U WORD
  • Unit: A
  • 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 DC Current (Address: 40096)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=40096, 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: "DC Current"
  address: 40096
  value_type: U_WORD
  unit_of_measurement: "A"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Esphome Web 4C96D0]

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


💡 Engineer's Insight

Analysis: Measures the direct current flowing through the monitored DC circuit (Amperes).

Troubleshooting: Zero reading may indicate no load, open circuit, or faulty current sensor. Check for continuity and sensor health.