Paper Title
PLC based Interlock Four Door System

Aiming at enhancing the probity of the automatic door operation micrologix 1400 programmable logic controller (PLC) was used as the core of the door interlocking system. In this paper we are centering on programmable logic controller used for door interlocking system which will be open at doorway and at exit. This door interlock controller can provide power and control for four doors. The PLC logic allows only one door , in any defined area to be unsecure at a time . The requests for a access or requests for accesses while another door is unsecured are denied to maintain highest level of control . Control system provides the various clues which are used to operate a nuclear facility. In some cases operators record these clues for use in day to day services. The information recorded assist the operator valuate the current status of the system and proceeds action if the status are not as expected. In this paper PLC programmed in “ladder language” which is strongly resembles with the relay logic. PLC ladder logic allows the programmer (the person writing the logic) to see any issues with the timing of the logic sequence more easily than other formats. PLC interface some input and output with a hardware device and it operate with the help of programmer. Here an Allen Bradley PLC is used to control the virtual model of a door control module. Door interlocking system is important from security point of view. Index terms- PLC , HMI , SMPS Micrologix 1400, ladder logic ,NO , NC