PC-Sim: Festo FPC 404 PLC simulator
This PLC simulator software is included in the AW-SYS
package. It simulates the
Festo PLC model FPC 404.
This window contains an image of the PLC. Obviously, the displayed image changes
according to the model being used. The window has been developed to display a
unit as similarly shaped as possible to an actual PLC. Passing to an actual PLC, if
desired, will then be an easier task. All the windows incorporate digital input and output
status LEDs. Just like in an actual PLC, an input LED ON status indicates that the linked contact
is closed; an output LED ON status indicates that the corresponding output has been
16 push buttons/switches are available in the PLC window. They are used for the control
of digital inputs when only the PLC is employed (without the simulated equipment) or when
PLC inputs are not all connected to the equipment.
These push buttons/switches may either function as push buttons or as switches; the
different arrangement indicates the proper function:
where the double arrow and single arrow indicate a toggle (bistable) function or a
one-shot (monostable) function, respectively.
The Ladder Diagram is certainly the most widely used programming language for PLC. It
is a graphic programming method. An electrical wiring diagram including a sequence of several circuits is
constructed between two vertical lines representing the power supply. The
PLC carries out each command in sequence when a user program is run.
The PC-Sim ladder editor allows easy editing of the program by combining fast
operations performed with the mouse and powerful advanced editor options: e.g.
The diagram is organised using the tools available in the Tool Box and the Popup menus which become
available by clicking the mouse right button. A check for syntax accuracy of the
operands, which may well be introduced as symbols, is carried out on completion of each
type-in operation. When the implemented program is run, the editor itself allows
debug information to be displayed. Different colours are used to
distinguish and display elements such as closed
contacts, energised coils and electrical flow. Colours will be real-time
updated according to processing results and variations of field signals.
When simulating a PLC FPC 404, this window must be used to preset timers and counters
values. Unlike the other simulated PLCs, the program editor of this particular PLC does
not allow these operations to be carried out .
Values, as preset in this window, are saved in a project file and reset when the file is
The remaining windows included in the program are common to all PLCs. For a more
detailed description see PC-Sim: the PLC simulator.