The SimSeny simulator is a data acquisition card simulator software for the development and test of computer applications for industrial control. It works simulating the behaviour of a given data acquisition card, the electrical signals connected to its pins and the physical behaviour of the processes to control.
The simulator makes possible the development of this control software without requiring the physical presence of the data acquisition card in the computer. Then, it is possible to validate the applications developed without any need for the card itself nor for the electronic circuits connected to it.
It has been designed in order to be transparent to the programmer and independent of the programming platform and the data acquisition card elected.
In order to understand the simulator, let me to explain its philosophy. Figure 1, “Relationship of the different blocks that compose the application.” shows the components of a computer based industrial control system that uses a data acquisition card. In general, the software application interacts with the data acquisition card through drivers provided by the card manufacturer. In the case of Microsoft Windows, these drivers are usually dynamic link libraries (DLL) or ActiveX library (OCX). The card is directly controlled by the drivers, which have access to its registers. Finally, the card is connected to the industrial process through electrical connections by appropriate sensors and actuators.
Figure 2, “Relationship between control system and components of the simulator.”Figure 2 shows a diagram of the blocks that form the simulator and how they are inserted in the industrial control system. The main idea is to capture all the calls to the functions of the card library and decide if they are to be directed to the simulation system or, again, to the data acquisition card.
The basic components of the simulator are:
A specific software module for the particular programming environment and data acquisition card pair employed. Its work is to capture all calls to the card functions made from the control application. The captured cards functions captured still can employ the real card or, if the user decides to use the simulator, the task of the module will be to convert the specific calls to the card to an independent format and transferred to the simulation system using a dynamic link library provided with the simulator.
A dynamic link library (DLL). This module is responsible for putting the developed application in contact with the viewing module of the simulator. Basically, it tries to make the design of the adapter module described above as simple as possible, facilitating its development. It also tries to separate the simulator and viewing module to allow the execution of the user application in a different computer.
An electrical signal viewer. The viewer module permits physical outputs to be shown and physical values to be entered in the simulated data acquisition card inputs, both for digital and analog signals.
A set of physical process models. The simulator includes a set of process models that simulate the physical and electronic behaviour of certain processes when activated.
