Meter/CT is necessary under the following use cases:

• Zero Feed-in to the grid (Export Control Function);
• Manage Battery to Charge / Discharge (Hybrid or AC Coupled Series);
• Load consumption monitoring;

Compatible Meter List

Compatible Inverter List

Note: ¹ USE CT ONLY; ² USE METER ONLY;

Take DDSU666-CT 200A/5A - ADD1 for example, it includes the Energy Meter, Current Transformer (200A/5A CT, 1m length), RS485 cable(10m length) and RJ45 connector.

Installation

Please install the meter between the grid and all home loads/other generators.

Below is a typical system diagram of single-phase inverter with a single-phase meter w/ CT

The standard meter ADD1 is usually installed at the main distribution box before all home loads, while meter ADD2 can be installed to monitor production from the other PV inverter or generator on the same platform - SolaX Cloud. Below is a typical diagram with one PV inverter and Hybrid/Fit energy storage system solution.

For more system details, please refer to this article Export Control Function

PIN Definition of SolaX Inverter and meter

As shown in the above figure, single-phase meter should be connected to PIN 4&5 at the bottom of the inverter via the RS485 cable. The default length of the cable is 10m. Installer can cut it shorter in accordance with the actual installation condition. If longer length is required, we suggest to use STP (Shielded Twisted Pair) RS485 cable:

If you check the label on smart meter, you will find the connection diagram as below:

• PIN 1&2 connects to L wire and N wire from the mains;

• PIN 9&10 connects to CT Red and CT Black;

CT Clamp should be clipped onto the L wire of the mains. As mentioned before, the position should be between the grid and all home loads/other generators.

Note: CT arrow should be pointing to the inverter direction

• PIN 24&25 connects to PIN 4&5(RS485_A & RS485_B) of SolaX Inverter via RJ45 connector;

Set Export Control function via LCD

For meter or meter with CT, please choose “Meter”;

For standable CT installation, please choose “CT”;

Note: Installer password is required after selecting “Setting”.

For more details, please refer to this article Export Control Function

Once set, the main screen will start counting down the checking time, and show “Normal” if everything is installed correctly.

Things to check if it shows an error like “Meter Fault”

In case of a "Meter Fault", please check the following three aspects:
1. Solax Meter Check

1. Wiring Check
2. Meter Setting Check

Solax Meter Check

Firstly,check whether the meter belongs to Solax or notIf not, please use the Solax meter.

Wiring Check

To fix the "Meter Fault," check the RS485 cable connection. The DDSU666-CT is compatible only with single-phase inverters. Ensure the correct connector type and pin configuration are used. If the fault persists, verify that the RS485 cable pins are securely connected at both ends. Please refer to the diagram below, and for more details, please refer to the user manual.

Taking X3-Hybrid as an example：

When connecting the meter to the X3 Hybrid G4,Please note that the pin definitions from the meter to inverter are 24 to 4, and 25 to 5.

Meter Setting Check

By pressing the "→" button on the meter, you can check the meter's parameters.

First, you can view the verification method and baud rate.

Second, you can view the communication address.

Third, you can view the voltages of L1, L2, and L3. Pressing“—>” three times will show UA, UB, and UC, corresponding to L1, L2, and L3

Next, you can view the current of L1, L2, and L3. Press the “→” button to see IA, IB, and IC, corresponding to the currents of different lines.

You can view the power of L1, L2, and L3, displayed as PA, PB, and PC.

You can view the power factor of L1, L2, and L3, displayed as PA, PB, and PC.

If you find that the settings do not match the above, please follow the instructions to change them

The default code of the meter is 701.Press the set button and enter the setting page. Press the right click to change the number of the ones,just continue pressing and then the number will add from 1 to 0.

Next, let's review the specific setting methods for some key settings.
After viewing the meter parameters, we will now focus on how to set them:

1. Current ratio

2. Verification method

3. Address

4. Baud rate.
The detailed descriptions of these parameters are available in the meter's manual and will not be repeated here.

1. Current ratio

Current ratio，used for setting the input loop current ratio.

For the specific setting procedure, take the Current ratio as an example:

When you see "" on the screen, click SET to enter the number adjustment page, then click "→" to adjust the number size. After setting, press ESC to exit, and click "→" to set the next parameter.The same logic applies to the following parameter settings.

2. Verification method

3. Communication Address

4. Communication Baud rate :The baud rate is generally 9600.

If the fault persists, please verify the following two additional points in the Meter Setting Check:

1. Check if “Export Control” is enabled and “Meter” is selected;

2. Check the Modbus address in the setting. By default it should be “1”;

3. If the above steps do not resolve the fault, please contact SolaX service team for more assistance.

How to check the meter/CT installation is correct or not

1. Is there an error on the inverter (Refer to Troubleshooting Guide if so)
2. Set the inverter to OFF mode
3. Turn ON some house loads
4. Check the Pgrid value (Press DOWN button on the main screen)
   If positive, then the meter/CT direction is reversed. If negative, then the meter/CT direction is correct.