Teracom’s MODBUS RTU devices can be updated using two methods.
The first is by utilizing the built-in functionality of controllers that support the MODBUS RTU interface, such as TCW242, TCW260, TCW210, TCG140, TCG140-4, and more. Alternatively, the device can be updated using the MBRTU-Update software.
We have previously described the process of updating sensors with Teracom controllers in this post – “How to update MODBUS RTU sensors using TCW210-TH/TCW260/TCG140
In this article, we will demonstrate how to update Teracom devices using the MBRTU-Update software.
We kindly ask you to read this article carefully from start to finish, as each sentence is significant.

To ensure that the device update process goes smoothly and successfully, there are five essential elements that you need to have:

• MBRTU-Update software

The MBRTU-Update software is a specialized tool created for Teracom to update MODBUS RTU devices. To begin, download the latest version of the software from www.teracomsystems.com and extract all files to the same folder.

• A suitable USB-to-485 or 232-to-485 converter with a driver installed

It’s essential to have a suitable USB-to-RS485 or RS232-to-RS485 converter. Please note that not every converter is compatible, and for a guaranteed successful update, we recommend using TUB2104 (Teracom USB to UART Bridge converter). To connect the converter and the device, we advise using three wires – RS485+, RS485-, and Ground and ensuring short lines and a line terminator at the device.

• The device requires updating

Please note that the device to be updated must be in bootload mode and alone on the RS485 line.

• An appropriate power supply for the device

TUB2104 (Teracom USB to UART Bridge converter) passes through the power of the USB port. This is sufficient for most Teracom MB RTU devices, and no external power supply is required.

• The current firmware version of the device

For a successful device update, follow the steps below:

1. Install the converter driver

For TUB2104, this is done as follows:

• Download CP210x-Universal-Windows-Driver and save it to your computer

• Plug the TUB2104 into the USB port

• Open Device Manager

• Find the “Teracom USB to UART Bridge TUB2104” in the Other Devices section

• Right-click on it and select Update driver

• Point to the CP210x-Universal-Windows-Driver folder

• Wait for the diver to install

• You will find the device in the Ports section:


The COM port number (COM54) may be different.

Third-party converters should be installed in a similar manner.

2. Connect the device to the converter

Connect the RS485+, RS485-, and Ground lines between the converter and the device. Make sure there is only one device on the RS485 line. Depending on the type of sensor connectors, the following connection schemes are possible:



If you cannot power the sensor from the interface converter you are using, please use an external power supply by connecting it as follows:



3. Use an appropriate power supply

Use an appropriate power supply according to each device’s documentation and put the device into Bootload mode.

All Terracom MODBUS RTU devices are put into Bootload mode in the same way, but just in case, read this section in the documentation of the specific device:

• Press and hold the config button while powering on the device

• The LED will light up and stay on

• In the following 3 seconds, release the button and press it three times in quick succession

• The LED will flash once and then stay lit, indicating that the device has entered Bootload mode

• The device will remain in this mode until the next power off and is ready to be updated

4. Run the MBRTU-Update program

The following window will appear:


5. Select the COM port

Select the appropriate COM port and press Connect


6. Press Next

Press Next and select the file with which you want to update the device.
The file can be downloaded from www.teracomsystems.com.
If the file is correct, you will see the following message according to the device type:


7. Press Next, then Update

Press Next, then Update and wait for the process to complete.


8. Successful update

If the update is successful, the indication is as follows:


In case of an unsuccessful update, just repeat the process starting from point 4.


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