Remote Monitoring and Control of an Industrial Process via a Siemens PLC Training Kit

Remote access to industrial processes allows operators to supervise plants without being on site, but it also introduces communication and security issues. This paper describes a remote monitoring and control system for an industrial process based on a Siemens PLC training kit and an Ethernet-based communication link. Process values are read and setpoints written from a supervisory interface, and the delay, reliability and security configuration of the link are evaluated. In simulation, process values reached the supervisory computer with a mean latency of 39 ms (maximum 257 ms) over a one-hour test, and the PLC entered its safe state in every simulated interruption longer than 5 s.