Before you start

Before you begin, make sure:

The TQ B-Control Energy Manager EM 300 is physically installed and powered on
You have the serial number and device password (located on the identification plate)
If measuring currents above 63A, a current transformer is installed with:
- Secondary current: 5A
- Accuracy class 1 or better

Step-by-Step Instructions

1. Connect the meter to the network

Connect an Ethernet cable to the LAN port on the EM 300
Verify the Network LED on the device lights up to indicate an active connection

For network infrastructure requirements and troubleshooting, see Infrastructure requirements for the gateway.

2. Access the meter settings

Open a browser on your device
Navigate to the meter's web portal
Log in using the password on the identification plate of the device

3. Enable communication via Modbus

Navigate to
Modbus TCP slave
Verify that Modbus TCP slave mode is enabled
Save the settings

4. Configure date and time

Navigate to
Date and Time
Enter the current date and time so consumption data is recorded correctly
Save the settings

5. Configure current transformer settings (if applicable)

If the EM 300 is installed with current transformers for currents above 63A, configure the transformer ratio.

Navigate to
Device settings
Enable External current transformers
Set the current transformer factor according to your installed transformer ratio
Save the settings

The secondary side of the current transformer must always be 5A.

6. Discover the meter in the commissioning wizard

The meter is now ready for the commissioning wizard. The gateway will scan the network to find available devices, which may take a few minutes. Once complete, the TQ B-Control EM 300 will appear on the results page.

FAQ

Why isn't the meter appearing in the commissioning wizard?

Check that the LAN cable is connected and the Network LED is active. Confirm that Modbus TCP slave mode is enabled in the web portal. Restart the gateway and wait for the network scan to complete.

How do I update the firmware of the meter?

Download the latest firmware from the TQ-Systems website and perform the update through the device web portal.

For detailed update instructions, refer to the official TQ-Systems documentation.

What current transformer specifications does the EM 300 require?

If using current transformers, the secondary side must be 5A and accuracy class 1 or better. For larger transformer ratios, use higher accuracy transformers — accuracy directly affects energy management performance.