Proceedings of the 2007 Winter Simulation Conference
S. G. Henderson, B. Biller, M.-H. Hsieh, J. Shortle, J. D. Tew, and R. R. Barton, eds.
ENABLING INDUSTRIAL SCALE SIMULATION / EMULATION MODELS
Michael Johnstone
Doug Creighton
Saeid Nahavandi
Intelligent Systems Research Lab
Deakin University
Pigdons Rd, Waurn Ponds
Victoria Australia
ABSTRACT
OLE Process Control (OPC) is an industry standard that
facilitates the communication between PCs and Program-
mable Logic Controllers (PLC). This communication al-
lows for the testing of control systems with an emulation
model. When models require faster and higher volume
communications, limitations within OPC prevent this. In
this paper an interface is developed to allow high speed
and high volume communications between a PC and PLC
enabling the emulation of larger and more complex control
systems and their models. By switching control of ele-
ments within the model between the model engine and the
control system it is possible to use the model to validate
the system design, test the real world control systems and
visualise real world operation.
1 INTRODUCTION
A 3D model coupled with Discrete Event Simulation
(DES) enables the creation of real world systems for visu-
alisation and analysis. With such powerful tools complex
systems can be modelled and a multitude of questions
asked about the system, questions ranging from analysis of
the system performance to “what if” scenarios. These
models can be made more valuable with the realisation that
they can be used to also test real world control systems.
Emulation, testing a control system via a computer model,
allows for the off line development of control programs
and testing of changes and numerous benefits detailed in
literature.
In a complex system it may be desirable to test only
parts of the control system. Glinsky et al. (2004) in their
modelling of a hardware-in-the-loop system incrementally
moved elements from the model into the real world as they
become available. This same concept can be applied to
emulation models. Control of elements within the model
can be passed back and forth between the external control
system and the simulation engine, allowing testing of indi-
vidual parts of a control system or the entire control sys-
tem.
Now with a 3D model of the system being controlled
by the real world control system a powerful visualisation
tool is available that can be used once the system is live.
Data from the control system can be used to drive the
model to represent what is occurring in the real world to
allow for monitoring of the system. The original model
created for validation of design or analysis can be used for
much more than just the original purpose.
The paper is laid out as follows. Section 2 gives a re-
view of the previous work in emulation while section 3 de-
fines hybrid environment and how this was achieved. Sec-
tion 4 gives the results for testing carried out with the
interface defined in section 3, while section 5 gives a
summary of the work and suggests areas where this new
environment is suitable.
2 REVIEW OF PREVIOUS WORK IN
EMULATION
The objective of emulation, or soft-commissioning as it has
also been referred to as (Schludermann et al.
2000;Versteegt et al. 2002), is to connect actual real world
control systems to simulation models to test the operation
of those control systems (Schludermann et al. 2000;Schiess
2001;McGregor 2002). Successful emulation implementa-
tions have been achieved in varying fields, for example,
baggage handling systems (Rengelink et al. 2002) and ma-
terial delivery systems (Lebaron et al. 1998).
Historically the testing of control systems was
achieved by connecting individual test or mock-up devices
to elements of the control system. This method of testing
required considerable time and resources and failed to test
the system as a whole (Whorter et al. 1997;Schludermann
et al. 2000). Due to this lack of adequate testing options
1028 1-4244-1306-0/07/$25.00 ©2007 IEEE