Edge System Design for Integration of S7-1500 PLC Communication with Mobile Devices via OPC-UA and MQTT Protocols

The complexity of devices from different manufacturers with different communication protocols is a challenge of Industry 4.0. In addition, Industrial Internet of Things (IIoT) affects Programmable Logic Controller (PLC) implementation for remote control and easy accessibility, so portable Human Machine Interface (HMI) are required. Integrating mobile devices as portable HMI is an option but requires special attention to the communication network. Therefore, an edge system is a solution to overcome the communication challenges between PLCs and mobile devices, with the condition that it must low latency and jitter.

This research aims to design and implement an edge system by integrating Siemens S7-1500 PLC communication with mobile devices through OPC-UA and MQTT protocols. The results of the edge system implementation are evaluated by analyzing the latency and jitter of the system to determine the effect of the amount of data on the data transmission time. The test is conducted by measuring the latency of the edge system which is the sum of the latency of the OPC-UA and MQTT communication protocols.

The analysis of the local network scheme shows a correlation coefficient of 0.997 indicating a very strong relationship between the amount of data and latency with the variable amount of data contributing 99.4% to latency. While in the internet network scheme, the correlation coefficient of 0.605 indicates a strong relationship between the two variables with the amount of data variable contributing 36.6% to latency.