Simulation-Based Development of Safety Related Interlocks - Simulation and Modeling Methodologies, Technologies and Application - page 160

or tools and fully setting the system parameters. Later in development, the same tech-
niques could enable testing and validating larger entities. Development of simulation
models could be less tedious and they could be utilized also by companies performing
out-sourced development phases. In our approach, we assume that a simulation model
of the process to be controlled is already available. In creation of a simulation model of
the controlled system including both the parts of the control system and the controlled
process, we utilize model transformations that are commonly used in model-based de-
velopment approaches, such as MDA of OMG.
Model-Driven Architecture (MDA) is an initiative of OMG that encourages the use
of models in software development as well as re-use of solutions and best practices.
MDA identifies three types of models which are Computation Independent Model (CIM),
Platform Independent Model (PIM) and Platform Specific Model (PSM). [10]
In MDA, the development starts from CIM models and proceeds to PIM models and
finally to PSM models which are the most detailed ones and often source models for
code generation. In our approach, the focus is in PIM and PSM models with the goal
of being capable of utilizing both PIM and PSM models in creation of simulation mod-
els. Thus, for example, a preliminary (early) simulation model could be created based
on PIM and used for evaluating control strategies. Later, after selection of the control
system vendor, the model could be refined to PSM level and simulated in conjunction
with vendor specific functions in order to obtain more precise results.
In addition to our approach (see [20] and [6]), the use of model-based techniques
in the automation domain has been recently proposed by several projects and papers.
However, not all of these approaches identify and highlight simulation as an essential
and beneficial part of development. The approach of the MEDEIA project, as discussed
by Strasser et al. [15] and Ferrarini et al. [4], is based on Automation Components
- composable combinations of embedded hardware and software including integrated
simulation, verification and diagnostics services. In their approach, the simulation of
models will be based on their interfaces, behaviour and timing specifications using IEC
61499 as a basic simulation model language [14].
Another application of model based techniques to development of industrial con-
trol applications has been presented by Tranoris and Thramboulidis [16]. In their ap-
proach, the design and deployment of applications is addressed by means of the function
block (FB) construct of IEC 61499. Model transformations are used to create function
block models. In the paper, they dont address simulations but similarly to the MEDEIA
approach, FB models could possibly be used with simulations of the process to be
controlled.
In both the approach of MEDEIA and that of Tranoris and Thramboulidis, simula-
tions could be supported with the implementation technology (IEC 61499) of produced
applications. The essential difference to our approach is that we aim to support sim-
ulation with a simulation language so that, for example, basic simulation functions of
simulation tools could be fully exploited. These functions are listed in [2] and include
saving and loading current and initial states, freeze, run and replay simulation, working
in slow and fast mode and support for malfunction situations.
Furthermore, we identify simulation as a beneficial and important activity also in
case of model-based development. We claim that also model-based development