Modbus Protocol on Raspberry Pi 3 using Serial GPIO Ports

Question

Hello There,

I want to make use of Modbus Protocol on my Raspberry pi 3 model B. I am Complete Beginner. After some Research i Found Some information about Modbus Protocol. i found these Libraries by which i can Use Modbus Protocol on Raspberry pi.

LIBMODBUS

PYMODBUS

MODBUS-TK

Please Suggest me that which one will be better to use.

As I have to communicate with MODSCAN 32 using my Raspberry Pi by RS232 circuitry, i have bought one

so I am quite sure that I need to make Raspberry Pi as SLAVE device. Because I am little confused with that please help me out.

Also Please Provide if any sample code is available to you, it will help me alot to understand better.

Thank you in advance

mconners · Answer

I'm not familiar with the modbus libraries, but that is just a typical c compiler error when it can't find an include file. Either you didn't install the modbus package as directed, or they left out an instruction. you can add the -I command line option to tell the compiler where to find the directory where the include file is located. See the following. https://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Directory-Options.html Mike

Robert Peter Oakes · Answer

Hi there, I have a better suggestion , try using Node-Red and the Modbus plugin, if you are a beginner then this I think will be an easier route to go, I have loads of Node-Red videos on my channel and alot of them use Modbus to talk to a thermal imaging camera and other devices Node Red is included with the Raspberry PI image and it is easy to add the Modbus plugin right from within Node-Red UI, look for the pallet manager. The plugin makes it so much easier to talk to modbus devices and node-red will allow easily to configure workflows and displays without the need for extensive coding. You can code stuff if you want but I would suggest getting to know Modbus first and then go from there. If you need help with Modbus I can help, I just have never needed to use the python interfaces. Regards peter Oh, my channel is https://www.youtube.com/thebreadboardca If necessary i will create a video for E14 and post it here to help, I have many devices I can choose from

Robert Peter Oakes · Answer

Sorry, missed the other part of your question, the, an Arduino may make a better Slave device and there is a sketch for that, just search for Arduino and Modbus. Is there a reason you have to use MODSCAN 32, this seems to be more of a debug tool, it this an assignment or something, perhaps you can provide a little background info so others can also help