Digital circuit is a combination of a digital chain of the output is only dependent on the input current and is independent of input or output earlier. The method is often used to design digital circuits are combined using boolean algebra or Karnaugh map. Zelio Soft 2 software is derived from the company Schneider Electric that are used to create a PLC program (Programmable Logic Controller). Zelio Soft 2 has two models in making the program, which uses ladder diagram (LD) and fuction Block (FBD). If in making a program using FBD then we use a lot of logic gate elements, such as a full adder, multiplexer, decoder, standard logic gates. From the results of the design shows that the Zelio soft 2 makes it easy to analyze digital circuit combination. In addition to simulating the design of digital circuits can be implemented using any combination of Zelio logic.

Keywords: Zelio Soft 2, Full Adder, Multiplexer