A Java']Java Virtual Machine for smart sensors and actuators

Java Technology enables systems built with different computing platforms to act as a homogeneous entity, where all components are compatible with each other, not only at the executable code level but also in the way that they communicate, store and deal with data. Besides the utilization in the higher levels of SCADA (Supervisory Control and Data Acquisition) systems, Java can also be utilized in devices found on the field level, where sensors and actuators are. However, those systems are known to have low resources in what concerns to memory amount and processing power, when compared with the traditional platforms capable of running Java. A Java Virtual Machine to run in low resources systems, based on 8-bit microcontrollers, was implemented. This virtual machine is specialized for data acquisition and actuation tasks, so it can be utilized in sensor and actuator systems. The developed prototype can run Java code previously installed on its internal memory or can dynamically download it from the network. For downloading the Java code and to communicate with other systems, the developed prototype was built with support for CAN (Controller Area Network) communications.