1. A system comprising: an interface means for establishing communication between an application and an control program of a programmable logic controller; and a shared memory area initiated by the application or the control program of the programmable logic controller, the shared memory area including an input memory and an output memory, the application enabled by the interface means to write input data only to the input memory and to read output data only from the output memory without directly communicating the input data or the output data through the control program.