A32 Pro Modbus Register 100: S5140 Channel 1 Voltage - Fresh Water Tank Level Sensor (240-33ohm)
Technical documentation for Modbus register 100 on A32 Pro. Data type: U WORD. Includes Python and YAML configuration examples.
January 16, 2026
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1 min read
Technical Definition
The register S5140 Channel 1 Voltage - Fresh Water Tank Level Sensor (240-33ohm) at address 100 is used to monitor s5140 channel 1 voltage - fresh water tank level sensor (240-33ohm) on the A32 Pro.
- Protocol: Modbus RTU
- Data Type: U WORD
- 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 S5140 Channel 1 Voltage - Fresh Water Tank Level Sensor (240-33ohm) (Address: 100)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=100, 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: "S5140 Channel 1 Voltage - Fresh Water Tank Level Sensor (240-33ohm)"
address: 100
value_type: U_WORD
unit_of_measurement: "V"
Connection Diagram
Here is the standard RS485 wiring for this configuration:
graph TD
PLC[Host Controller / Home Assistant]
Device[A32 Pro]
PLC -- "A+ (D+)" --> Device
PLC -- "B- (D-)" --> Device
PLC -- GND --> Device
💡 Engineer's Insight
Analysis: Fresh Water Tank Level Sensor (240-33 Ohm). Voltage input representing tank level based on resistance.
Troubleshooting: Zero indicates an empty tank or open circuit. Could be sensor failure or wiring issue.