DDSU666 (Direct chint meter ) + mbpoll Command Reference

Version : 1.0 Prepared For : Field & Deployment Teams Platform : Raspberry Pi / Linux Tool : mbpoll 

 

 

 Purpose 

 

 

 This document explains how to communicate with the CHINT DDSU666 Direct Smart Meter using Modbus RTU and the mbpoll tool. 

 It covers: • Reading electrical parameters • Setting meter addresses • Verifying communication • Preparing for OpenEMS integration 

 2. Hardware & Software Requirements 

 Hardware • DDSU666 (Direct Version) • RS485 → USB Converter • Raspberry Pi / Linux PC • Correct RS485 wiring (A(converter)↔24(meter com-port terminal), B(converter)↔25(meter com-port terminal), GND recommended) 

 Software Install mbpoll: 

 

 sudo apt update sudo apt install mbpoll 

 

 Check serial port: 

 

 ls /dev/ttyUSB* 

 

 Example output: 

 

 /dev/ttyUSB0 

 

 

 3. Communication Parameters (Confirmed) 

 

 

 

 

 

 Parameter 

 

 

 Value 

 

 

 

 

 Protocol 

 

 

 Modbus RTU 

 

 

 

 

 Baud Rate 

 

 

 9600 

 

 

 

 

 Data Bits 

 

 

 8 

 

 

 

 

 Parity 

 

 

 None 

 

 

 

 

 Stop Bits 

 

 

 2 

 

 

 

 

 Format 

 

 

 8N2 

 

 

 

 

 Float Order 

 

 

 Big Endian 

 

 

 

 

 Addressing 

 

 

 0-Based 

 

 

 

 

 These parameters must always be used. 

 4. Standard mbpoll Format 

 All commands follow this format: 

 

 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 -r <register> -c <count> /dev/ttyUSB0 -a <id> -1 

 

 Where: •    <register> = Modbus register •    <count> = Number of values •    <id> = Meter address (NO.) 

 5. Electrical Parameters 

 Summary: 

 

 Voltage: 0x2000 Current: 0x2002 Active Power: 0x2004 Power Factor: 0x200A Frequency: 0x200E Energy: 0x4000 

 

 5.1 Voltage (V) — Register 0x2000 

 

 Meter ID = 1 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2000 -c 1 /dev/ttyUSB0 -a 1 -1 Meter ID = 2 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2000 -c 1 /dev/ttyUSB0 -a 2 -1 

 

 5.2 Current (A) — Register 0x2002 

 Meter ID = 1 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2002 -c 1 /dev/ttyUSB0 -a 1 -1 Meter ID = 2 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2002 -c 1 /dev/ttyUSB0 -a 2 -1 

 5.3 Active Power — Register 0x2004 

 

 Meter ID = 1 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2004 -c 1 /dev/ttyUSB0 -a 1 -1 

 Meter ID = 2 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2004 -c 1 /dev/ttyUSB0 -a 2 -1 

 

 5.4 Power Factor — Register 0x200A 

 

 Meter ID = 1 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x200A -c 1 /dev/ttyUSB0 -a 1 -1 Meter ID = 2 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x200A -c 1 /dev/ttyUSB0 -a 2 -1 

 

 5.5 Frequency (Hz) — Register 0x200E 

 Meter ID = 1 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x200E -c 1 /dev/ttyUSB0 -a 1 -1 Meter ID = 2 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x200E -c 1 /dev/ttyUSB0 -a 2 -1 

 5.6 Energy (kWh) — Register 0x4000 

 Meter ID = 1 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x4000 -c 1 /dev/ttyUSB0 -a 1 -1 Meter ID = 2 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x4000 -c 1 /dev/ttyUSB0 -a 2 -1 

 6. Reading Multiple Values 

 Use -c option to read multiple registers. 

 Example ( Voltage + Current Together) 

 

 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2000 -c 2 /dev/ttyUSB0 -a 1 -1 

 

 7. Meter Address 

 

 Register: 0x0006 

 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:int16 -0 \ -r 0x0006 -c 1 /dev/ttyUSB0 -a 2 -1 

 Example Output: [6]: 2 

 

 8. Changing Address 

 

 Only one meter connected. 

 Power cycle after change. 

 

 

 Change Address (2 → 1) mbpoll -m rtu -b 9600 -P none -s 2 -t 4:int16 -0 \ -r 0x0006 /dev/ttyUSB0 -a 2 -W -- 1 Power Cycle Turn OFF → ON the meter. Verify mbpoll -m rtu -b 9600 -P none -s 2 -t 4:int16 -0 \ -r 0x0006 -c 1 /dev/ttyUSB0 -a 1 -1 

 

 9. Health Check 

 Voltage should be 220–240V. 

 

 mbpoll -m rtu -b 9600 -P none -s 2 -t 4:float -B -0 \ -r 0x2000 -c 1 /dev/ttyUSB0 -a 1 -1 

 

 10. Common Issues 

 Timeout Errors •    Duplicate IDs •    Wrong wiring •    Wrong stop bits •    Multiple meters during setup 

 Incorrect Float Values Use -B option. 

 Current / Power = 0 

 Normal when: •    No load •    Bench testing 

 11. Deployment Workflow 

 For large installations: •    Connect one meter •    Convert to Modbus •    Set address •    Test voltage •    Install •    Repeat •    Never deploy duplicate addresses. 

 

 Connect → Configure → Test → Install 

 

 12. System Status 

 ✔ Modbus Enabled ✔ 9600 8N2 Confirmed ✔ Big-Endian Floats ✔ Multi-meter Bus Working ✔ Ready for OpenEMS