Esp32 Rs232 Modbus Register 278: Name Battery Current

Technical Definition

The register name Battery Current at address 278 is used to monitor name battery current on the Esp32 Rs232.

• Protocol: Modbus RTU
• Data Type: S 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 name Battery Current (Address: 278)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=278, 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: "name Battery Current"
  address: 278
  value_type: S_WORD
  unit_of_measurement: "A"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Esp32 Rs232]

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

💡 Engineer's Insight

Analysis: Tracks the flow of electrical charge into or out of the battery. Unit: Amperes (A).

Troubleshooting: Zero suggests no charging or discharging. Check battery state and system power flow.