Demonstration of Modbus Protocol for Robot Communication Using C#

Abstract

Purpose: The Modbus is the trusted name in the industrial automation communication domain. It is a pretty simple protocol to implement and so very popular to the industrial communication personnel. Nowadays, Some industrial robots are also capable of communicating through Modbus. So our robot researchers frequently face the challenge of communicating with Modbus-enabled devices or robots. They need to know the protocol in detail before integrating it into their project. Its learning curves are a bit higher because of the lack of document which is practical oriented. The protocol selection, packet structure, CRC, or LRC calculation need to maintain precisely as standards; otherwise, the Modbus exception may happen. We experience those scenarios. Through our practical experience, we learned what is required for a new researcher who wants to implement Modbus in their project. In this paper, we demonstrate the Modbus packet structure and implement it with several practical examples. Finally, to test the written code, we provide simple tools which are easy to use and customizable. The researcher can easily integrate into their research project. The complete project source code is available in Github.

Design/Methodology/Approach: The Modbus is the standard protocol to communicate between or among the devices. We need a better understanding of it and interface software to test around all aspects. Here we described some practical examples. The GUI is created using C# language inside the Microsoft Visual Studio. The application has several capabilities. In the TCP/IP mode, It can be a server or client. In RTU mode, it can play as a Master or slave device. We can also run two instances in a single system. To communicate between two running apps in RTU mode, we need virtual loopback software, two physical comm port, or two USB to Serial modules. For Modbus TCP mode, we can test within the system using the localhost address (127.0.0.1) or need an IP address for a different.

Findings/results: The robot researcher can find helpful information about communicating the robot through the Modbus protocol. The practical example can help them to create packet purser. The functional CRC algorithm code can be used for better understanding and implementation into their project.

Originality/Value: This work has some different features than other available utilities. We added features based on our research needs. Our created application is a little bit different from a professional approach. Various display formats are available in our GUI. That makes a difference in the originality of this work. Our GUI can be master, slave, server, or client, which is rarely available. 

Paper Type: Experimental-based Research.