CHINT DTSU666 / DSSU666 energy meter
This guide describes how to connect a CHINT DTSU666 or DSSU666 three-phase energy meter for DIN rail mounting (4TE) to the Currentt Navigator via Modbus RTU over RS485.
The CHINT DTSU666 and DSSU666 are three-phase energy meters with RS485 Modbus RTU interface. These meters are widely used in combination with solar energy installations.
Make sure each device on the RS485 bus has a unique Modbus address.
🔀 Variants
| Model | Description |
|---|---|
| DTSU666 | Three-phase four-wire (3P4W) |
| DSSU666 | Three-phase three-wire (3P3W) |
🔌 Connecting the meter
The meter is connected to the Currentt Navigator using a twisted pair data cable (for example CAT5 or CAT6 UTP). The cable contains two signal lines (A+ and B-) and optionally a ground connection. Always use a twisted pair for the signal lines — the twisting suppresses electromagnetic interference (EMI) and is essential for a reliable RS485 connection.
The RS485 connection is located on the terminal strip of the meter. The relevant terminals are:
| Terminal | Function | Description |
|---|---|---|
| 24 | A | Data line A |
| 25 | B | Data line B |
CHINT DTSU666 / DSSU666: RS485 terminals (24=A, 25=B)
Always use a twisted pair for the A and B signal lines. The twisting of the pair suppresses electromagnetic interference (EMI) and is essential for a reliable RS485 connection, especially over longer distances.
Connect the ground on one side only: either to the Currentt Navigator or to the meter — but never on both sides. Connecting ground on both sides can cause a ground loop, leading to communication errors or equipment damage.
Connecting to the Currentt Navigator
| CHINT DTSU666 / DSSU666 | Currentt Navigator |
|---|---|
| A (terminal 24) | A+ |
| B (terminal 25) | B- |
Bus topology
Preferably use a daisy-chain (series) topology. At short distances (< 25 meters), a star topology often works as well. Connect a maximum of 32 devices to a single RS485 bus. Place a 120 Ohm termination resistor at both ends of the bus.
The Currentt Navigator has a built-in termination resistor that can be enabled or disabled via software. By default, it is enabled.
⚙️ Configuration in the Currentt Navigator
After physically connecting the meter, the device must be added in the Currentt Navigator. This can be done in two ways:
Via the setup wizard (recommended)
- Click the settings icon (top right of the screen)
- Choose Setup wizard
- Follow the on-screen steps
Manual configuration
- Click the settings icon (top right of the screen)
- Go to Components
- Click the + button in the Meters section
- Select CHINT
- Choose the model DTSU666/DSSU666
- Specify what the meter will measure:
- Consumption and generation — the meter measures both consumption and feed-in (bidirectional)
- Consumption only — the meter measures consumption only
- Generation only — the meter measures generation only (for example, behind an inverter)
- Specify which phases the meter is connected to (L1, L2, and/or L3)
- Under Communication, select RS-485
- Set the communication parameters. The meter's default settings are pre-filled in the Navigator (see settings summary)
Additional options
- Measurement range: If possible, specify the measurement range in amperes that will be measured.
- Reverse meter direction: If the meter is physically installed in the wrong direction, the measurement direction can be reversed in software. This prevents the meter from registering consumption as generation (or vice versa) without physically reversing the meter.
- Use as PAP: This meter can also be used to measure the main connection (PAP, primary allocation point). In that case, select the "Use as PAP" option during configuration.
📋 Settings summary
| Parameter | Value |
|---|---|
| Brand | CHINT |
| Model | DTSU666 (3P4W) / DSSU666 (3P3W) |
| Type | Three-phase energy meter |
| Baud rate | 9600 |
| Data bits | 8 |
| Parity | None |
| Modbus address | 1 (default) |
| Programming password | 701 |
| Terminal 24 | A (→ Navigator A+) |
| Terminal 25 | B (→ Navigator B-) |
🔢 Setting the Modbus address
The DTSU666/DSSU666 is shipped with Modbus address 1 by default. The address can be changed via:
Via the display
The DTSU666/DSSU666 has three buttons: SET (confirm/cursor), ESC (back), and an arrow button (increment value).
- Press and hold SET for 3 seconds to enter programming mode
- The password screen appears. Enter the default password 701: use the arrow button to increment the digit and SET to move to the next digit
- After entering the correct password, press SET to open the system settings menu
- Navigate to the communication settings and select the Modbus address
- Change the address with the arrow button and confirm with SET
- Press ESC to exit the menu
🛟 Troubleshooting
| Problem | Possible cause | Solution |
|---|---|---|
| No communication | Wrong A/B wiring | Swap the A and B wires |
| No communication | Wrong Modbus address | Verify that the address matches in both the meter and the Navigator |
| No communication | Parity is enabled on the meter | Set parity to None (disabled) |
| Incorrect power values | CT ratio not configured | Configure the CT ratio via the meter's display |
| Negative energy values | Current transformers reversed | Reverse the CTs or swap the phase connections |
| Intermittent communication | No twisted pair used | Use a twisted pair for the signal lines |
| Intermittent communication | Termination missing | Enable the termination resistor on the last device in the chain |
| Timeout errors | Wrong baud rate | Make sure the baud rate is 9600 on both sides |
| Settings cannot be changed | Programming password incorrect | Default password is 701 |