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How to send data through Ethernet HTTP with industrial PLC


In this blog post, you are going to learn how to solve a communication problem that exists with conventional PLCs of the main brands in the market. Let's imagine that you want to automate a meat selection line that comes from the same place using a barcode scanner. Once the code is scanned, the piece of meat is redirected to its corresponding lane. The point is that the device that reads the barcode has to communicate with the PLC Arduino via Ethernet with HTTP instructions and the PLC has to receive it and act accordingly. After consulting the most important brands in the market, the general answers we have received are that:
❌ you cannot do it with your device or
❌ you have to buy another special PLC controller at a quite high price, pay for the program license and, of course, program it.

This is a waste of money, time and a real headache.


This problem is easily solved by the entire range of Industrial Shields' programmable logic controllers as they have a configurable Ethernet port by default, as well as having the versatility of working with various protocols that we will mention below. Since with the other brands it was quite difficult, if not impossible, to achieve this goal, with Arduino-based  Industrial Shields PLCs, it is not necessary to buy any license since:
✔️ it is Open Source programming with the Arduino IDE platform and
✔️ both in our page and in Arduino's one you can find many examples of real projects and source codes that can be used to develop each specific application.

Various protocols with Ethernet

First we have the HTTP protocol which is separated in:

  • HTTP Client: allows to create a request, send it to a URL and read the result. 

  • HTTP Server: which is the server that communicates with the client. 

In second place there is the MQTT protocol which consists of the M2M (machine to machine) communication with queue message type.

And finally the Modbus TCP/IP that is a Modbus variant used for communications over TCP/IP networks in industrial controllers for Arduino automation, connecting through port 502. It does not require a checksum calculation, since the lower layers already provide checksum  protection:

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