Embedded Execution Environment for Modular Firmware Structures

The rising pressure of competition forces the industry to more flexible production. The ability of effective lot-size one and small batch production is becoming an important requisite for success on the todays competitive markets. However, classical manufacturing plants are not suited for the new requirements of todays markets. Decentralized systems helped to save money for cabling of the automation devices, but changed nothing on the monolithic structure of classic industrial process and measurement systems. Such structures are not suited for fast reconfigurability. The emerging standard IEC 61499 – Function blocks introduces a distributed execution model, suited for fast reconfigurability. Unfortunately it is not widely used, as there are few automation devices that support IEC 61499 natively. Although there are runtime environments for IEC 61499, none of them is suited for use in cheap smart sensors and actuators, as memory size and computing power are too low on such devices. But direct integration of smart sensors and actuators would vastly improve and simplify the possibilities of designing and handling distributed control systems for e.g., manufacturing plants or building automation systems. This diploma thesis targets this problem, by developing an embedded execution environment for modular firmware structures with direct integration in IEC 61499 networks suitable for embedded systems with limited memory. First the requirements of a firmware execution environment will be identified by an use case analysis of the programming phase and the operational phase of a typical automation device. Based on the findings of the use case analysis the requirements for the execution environment are identified, which are the base for a first conceptual design for such an execution environment. The findings of the conceptual design are then used to modify the existing IEC 61499 runtime environment FORTE. The modification decreased the code size of FORTE for about 56% to 172076 bytes. Therefore it is now possible to run FORTE on cheap micro controllers, with limited ROM and RAM, commonly used in smart sensors and smart actuators. Thereby the granularity of a distributed system can be further reduced and therefore the available computing power can be better utilized, and the reuse and modularity of system parts can be increased.