Simulate Modbus

Well, first of all I wanted to apologize for leaving the blog standing still. Lately I have gotten into too many messes and I walk with the right time, justito.

Recently, I found myself in the need to develop a web application, to supervise an installation with a telemecanique automaton. As a communications protocol I preferred to use Modbus rtu. But I had to finish the project at home, and I didn't feel like setting up an automaton with the fuss of cables and so on, to do the tests. So I looked for a way to be able to simulate the operation and, luckily, I soon found the solution.

I used a free modbus simulator called Modbus_RcSim, the next thing was to find a way to communicate it with my application, for this I used VSPE, Virtual Serial Port Emulator. This interesting program allows us to do some interesting things with the series ports. In this case, I used it to create two virtual serial ports connected to each other. This way I could establish communication with RcSim and my app.

The rest of the work was to launch an application in Vb.net, which was able to read modbus and serve the data to php to make the web application. To be able to read modbus use a free modbus library called NModbus.

Authors: David

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