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Upower Modbus Register 13597: PV output Voltage

Technical documentation for Modbus register 13597 on Upower. Data type: INT16. Includes Python and YAML configuration examples.

January 16, 2026 1 min read

Technical Definition

The register PV output Voltage at address 13597 is used to monitor pv output voltage on the Upower.

  • Protocol: Modbus RTU
  • Data Type: INT16
  • Unit: V
  • 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 PV output Voltage (Address: 13597)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=13597, 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: "PV output Voltage"
  address: 13597
  value_type: INT16
  unit_of_measurement: "V"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

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

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


💡 Engineer's Insight

Analysis: Voltage at the PV output. Units are Volts (V). May reflect panel voltage or internal conversion stage.

Troubleshooting: Zero indicates no PV output. Check PV input, internal PV processing, and connections.