# DDSU666 (Direct chint meter ) + mbpoll Command Reference

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

1. #### 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)

<table border="0" cellpadding="0" cellspacing="0" class="MsoNormalTable" id="bkmrk-parameter-value-prot" style="border-collapse: collapse; width: 68.6905%; height: 160.172px;"><tbody><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">**Parameter**

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">**Value**

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Protocol

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Modbus RTU

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Baud Rate

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">9600

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Data Bits

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">8

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Parity

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">None

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Stop Bits

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">2

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Format

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">8N2

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Float Order

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Big Endian

</td></tr><tr style="height: 17.7969px;"><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">Addressing

</td><td style="width: 0%; padding: 0in 5.4pt; height: 17.7969px;" valign="top" width="288">0-Based

</td></tr></tbody></table>

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 &lt;register&gt; -c &lt;count&gt; /dev/ttyUSB0 -a &lt;id&gt; -1

Where:  
• &lt;register&gt; = Modbus register  
• &lt;count&gt; = Number of values  
• &lt;id&gt; = 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