Gateway for Profibus communication between a PLC and embedded system

In this paper, It proposes a simple., but effective and economical Gateway to connect a Siemens PLC, with an embedded device. This design allows a reliable Profibus communication with differential voltage, having a microcontroller working as slave. The experimental tests show that standard chip MAX485 does not guarantee the connection compared it with the proposed Gateway and by means of signal analysis, errors are identified. Through a processing of the received signal by the embedded device and the Profibus frames determine the parameters that avoid errors and conflicts in communication where embedded device performs signal processing and retransmits to PLC. This Gateway can be used with others field devices due analog electronic circuit provides correct levels voltage and impedances coupling with which an excellent behavior is obtained.