How to Use Teltonika TRB255 IoT Gateway with Blynk?

Hello. I am working on a project to connect a simple PLC to Blynk dashboard. I have tried to use Arduino MKR1500 board, which got disconnected with network frequently.
I am now trying to use Teltonika TRB255 IoT gatway for LTE CAT-M1/NB-IoT connection. TRB255 is stable with LTE CAT-M1 connections.

My question is: how can I link TRB255 with Blynk dashboard? There is no instructions I can find on the web.


I don’t think you can link it directly.
The datasheet on this device seem to indicate that it’s a gateway, to allow devices to connect to the internet. Effectively performing the role of a router or hotspot.

A device connected to this gateway would be able to connect to Blynk, if it were a supported device running Blynk firmware, or if it had an API that could be queried via Blynk (and if the limitations of that system met your use-case).

Was this due to a poor internet connection, or are you talking about frequent disconnections from the Blynk server.

It might help if you explained more about this, and your network infrastructure. That way we might be able to point you in a better direction.


Thank you Pete for your help on this.

I was previously using MKR1500 board with an IoT SIM. I found the MKR1500 board frequently lost connection to cloud dashboard (Arduino dashboard or Blynk dashboard). I need to press the reset button on the board, or reconnect to PC’s USB port to get the MKR1500 re-connected to the cloud dashboard.

MKR1500 seems to be not working reliably for me. This is the main reason I am now trying the Teltonika TRB255 gateway for getting a reliable internet connection to cloud dashboard.

I am now using TRB255 for internet connection, MKR1010 board with MKR ETH shield for Ethernet link to PLC and to TRB255.

I will try out a few examples to test.

Have you looked at the Sketch Builder examples, or the examples installed with the Blynk library?


Hi Pete,

Thanks for your suggestion. I have looked at the examples installed with Arduino IDE and Blynk library.

I have tried MKR1400 + MRK RS485 shield to communicate with a Schneider M221 PLC controller via Modbus RTU. It worked OK.
I have tried MKR1010 + MRK ETH shield to communicate with a PLC controler via Modbus TPC. It worked OK.

I have now set up the following three connections to Blynk dashboard, side by side.
A: MKR1010 board+ MRK Eth shield, and TRB255 gateway with 1NCE SIM
B: MKR1500 board with 1NCE SIM.
C: MKR1400 board with 1NCE SIM.

I am now comparing the reliability of mobile connection to Blynk dashboard for A, B and C settings.

If they can keep to stay online to Blynk dashboard for over 3 days. That’s going to be OK.
Ideally, I’d like to use MKR1500 board + RS485/Eth shield. (as MKR1400 is at end of life status; and to use TRB255 gateway is more expensive.)

My question now is: if one of the board dropped offline to Blynk dashboard, does it trying to reconnect itself back to Blynk dashboard automatically, or I need to manually to power off and power on again to re-establish mobile connection to Blynk dashboard? Or is there sketch example on how to allow MKR1500 board to reconnect to Blynk dashboard, ideally with a delay timer of i.e. 10 mins after drop offline?


That’s very easy for me to achieve with an ESP8266 or ESP32, but I’m not familiar with your hardware, so I can’t really advise about that I’m afraid.


I’d like to explore the ESP8266 or ESP32 boards.
Would you please suggest a ESP32 board, a NB-IOT shield, a ethernet shield / RS485 shield, which can use a SIM to link to Blynk dashboard, also be able to use Modbus TCP or Modbus RTU to communicate with a PLC controller?


I don’t understand the Ethernet and SIM combination.
Is the Ethernet port to connect to your MODBUS? If so then you need to explain more about your architecture.


Hi Pete,

Thanks for your reply.

I am now testing to use Blynk.connected() in the loop() to check the online/offline status of MKR1500 board to Blynk server. If false = Blynk.connected(), it will run the Blynk.begin(xxx) in the loop() to reconnect to Blynk server.
I will wait to see can the MKR1500 board be able to reconnect to Blynk server, if it’s been dropped offline for a short while.

Also, I will order 2no. Arduino Nano ESP32 boards, to get familiar with ESP32 boards for better working with Blynk.


You shouldn’t be using Blynk.begin in this way. You should manually manage your WiFi connection then use Blynk.config() and Blynk.connect() then check if the WiFi connection and Blynk connection are good, and re-connect if not.

I don’t know what these boards are, but if you’re going for an ESP32 then I’d go for the ESP32 Devkit V4 boards.