Remote access solutions for industrial control systems

The majority of current industrial control systems are easily configurable and they offer a lot of data about the state of the controlled process. Unfortunately, most of this information is only accessible locally, making difficult the integration of these systems into a centralized control and information management system. To solve this problem, it is necessary to provide the control systems with remote access capabilities. The paper investigates some of the usual solutions for remote access - analog PSTN (public switched telephone network) communications, GSM based communications (using SMS, short message system; using V32 data connections; using GPRS, general packet radio service, connections) and Ethernet based communications. Hardware requirements and how to implement each of these solutions into different embedded systems are also analyzed. Advantages and disadvantages of each solution are studied considering different criteria - price, communication speed, security, implementation effort and user friendliness -and a procedure for selecting an appropriate remote access solution for a real application is presented.