# DTSU666 3‑Phase + mbpoll Command Reference --- # 🔌 Standard Communication Settings (DTSU666) Most DTSU666 meters use:

Protocol : Modbus RTU Baud Rate : 9600 Data Bits : 8 Parity : None Stop Bits : 2 Mode : Big‑endian Table : Input Registers (FC04)

Base communication block used in all commands:

-m rtu -b 9600 -P none -s 2

--- # 🧠 Critical Flags (Important)

--- --- ## 🔹 Phase‑to‑Neutral Voltages (L1‑N, L2‑N, L3‑N) Register: `0x2006`

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x2006 -c 3 \ /dev/ttyUSB0 -a 1 -1

--- ## 🔹 Line‑to‑Line Voltages (L1‑L2, L2‑L3, L3‑L1) Register: `0x2000`

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x2000 -c 3 \ /dev/ttyUSB0 -a 1 -1

--- ## 🔹 Phase Currents (L1, L2, L3) Register: `0x200C`

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x200C -c 3 \ /dev/ttyUSB0 -a 1 -1

--- ## 🔹 Total Active Power (kW) Register: `0x2012`

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x2012 -c 1 \ /dev/ttyUSB0 -a 1 -1

--- ## 🔹 Frequency (Hz) Register: `0x2044`

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x2044 -c 1 \ /dev/ttyUSB0 -a 1 -1

--- ## 🔹 Total Active Energy (kWh) Register: `0x4000`

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x4000 -c 1 \ /dev/ttyUSB0 -a 1 -1

--- # 🔁 Continuous Polling Example (Every 5 Seconds)

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x2006 -c 1 \ -l 5000 \ /dev/ttyUSB0 -a 1

--- # 🔢 Change Slave Address (Only One Meter Connected) ⚠ Use Holding Registers (Function 03) for configuration. Register: `0x002E`

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 4:int16 -0 \ -r 0x002E \ /dev/ttyUSB0 -a 1 -W -- 5

Changes slave ID from 1 → 5. --- # 🧪 Quick Communication Test Fastest health check:

mbpoll -m rtu -b 9600 -P none -s 2 \ -t 3:float -B -0 \ -r 0x2006 -c 1 \ /dev/ttyUSB0 -a 1 -1

If you see ~230V → communication confirmed. --- # 🚨 Troubleshooting Quick Guide