Jk Rs485 Bms2 Modbus Register 4756: Bms2 power

Technical Definition

The register bms2 power at address 4756 is used to monitor bms2 power on the Jk Rs485 Bms2.

• Protocol: Modbus RTU
• Data Type: S DWORD
• Unit: W
• 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 bms2 power (Address: 4756)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=4756, 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: "bms2 power"
  address: 4756
  value_type: S_DWORD
  unit_of_measurement: "W"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Jk Rs485 Bms2]

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

💡 Engineer's Insight

Analysis: Instantaneous power consumption or generation. Units: Watts (W). Positive for charging, negative for discharging.

Troubleshooting: Zero power suggests no load, battery fully charged/discharged, or communication error. Negative power might indicate a fault if charging is expected.