Event-triggered Component Research Articles

An approach to implement a Programmable Logic Controller from real-time software components

This paper proposes an approach to implement a Programmable Logic Controller (PLC) from real-time software components following the International Industrial Standard IEC61499. According to this standard, a Function Block is an event triggered component owning data and a control application is a network of blocks that have to satisfy end to end response time bounds according to user requirements. To correctly deploy these blocks in feasible OS tasks of the PLC, we propose a hybrid scheduling approach that combines static non-preemptive and online preemptive policies where the static policy allows the construction of sequencings that satisfy temporal constraints. We transform these sequencings into conditional OS tasks of the execution environment before we apply the online policy to check the preemptive feasibility of these tasks.

A deployment methodology of real-time industrial control applications in distributed controllers

This paper deals with the deployment of industrial control applications in distributed devices (considered as multi-tasking Programmable Logic Controllers (PLCs)). These applications are developed according to the component-based standard IEC 61499. In this standard, a function block is an event triggered component and the application is a network of distributed blocks on several devices. To deploy these blocks in feasible OS tasks of the execution support, we propose a hybrid scheduling approach allowing in particular to check according to specifications the temporal behavior of the application in devices and also on the communication network. This approach is based on static and dynamic policies. The static policy allows to construct OS tasks from function blocks, whereas the dynamic policy allows their scheduling at run-time.

An optimised simulation of component-based embedded systems in manufacturing industry

This paper deals with an optimised simulation of embedded systems following the international standard IEC61499 in which a Function Block is an event triggered component owning data and an application is a network of blocks that have to satisfy properties described in user requirements. We design these components in different abstraction levels of a hierarchy to control the development complexity. To achieve a feasible simulation, we formalise at first-time the FB concept by defining the Control Function Module (CFM) and the Virtual Plant Module (VPM). We propose thereafter a technique processing temporal deadlines for control modules and we define in the system behaviour critical scenarios where properties can be violated. We apply the simulation around these scenarios by applying a fault injection technique to optimise the system validation and to consider its hierarchy, we propose a simulator architecture based on the master-slave model where a slave injects faults in each level of the hierarchy, whereas the master chooses the best values of these errors to generate critical scenarios.

A DEGRADED SCHEDULING GENERATION OF A COMPONENT BASED APPLICATION

This paper deals with control applications designed using the component-based standard IEC 61499. In this standard, a function block is an event triggered component and an application is a function blocks network. Supposing end to end delays on applications behavior, the hard temporal validation of FBs networks may be not feasible. We propose to weaken these delays by tolerance constraints deduced from specifications. Exploiting the (m, k) model to specify these constraints, we propose a schedulability analysis generating a degraded scheduling to use by a sequencer at run-time.