Issue Number: Vol. 5, No. 1
Year of Publication: 2015
Page Numbers: 21-43
Authors: Claude Ziad Bayeh
Journal Name: International Journal of Digital Information and Wireless Communications (IJDIWC)
- Hong Kong
DOI:  http://dx.doi.org/10.17781/P001551


The “Manual Logic Controller” also called MLC, is an electronic circuit invented and designed by the author in 2008, in order to replace the well known PLC (Programmable Logic Controller) in many applications for its advantages and its low cost of fabrication. The function of the MLC is somewhat similar to the well known PLC, but instead of doing it by inserting a written program into the PLC using a computer or specific software inside the PLC, it will be manually programmed in a manner to have the same functionality of the PLC. The program is done manually by connecting wires between coils and contacts of relays, in a way to form a program without using any memory or microcontrollers. It gives the same functionality of the PLC for small and medium programs, and moreover the contacts can support high currents, not like the PLC which supports only small current rate on its contacts. The lifetime of the MLC is much longer than the PLC, and its maintenance is much simpler, because anyone can make it or repair it. The MLC will not be defected by the variation of the input voltage and the input frequency because it is fabricated using mechanical relays which perform even if the electricity is not stable. The Grafcet and the Ladder parts of the MLC, are much simpler than the PLC for some applications, therefore, MLC is highly recommended for small and medium applications for its advantages over the PLC which are presented in this paper.