We have all seen escalators at shopping malls,airports,etc .Without any further a due let’s see how we can program escalators using PLC
(1)Let’s assume that the escalator does not move until someone approaches it. (2)When someone approaches the escalator and turns on pass detection switch:0, the illumination lamp lights and the escalator starts to move. (Escalator movement is up only.) (3) The person is carried up by the escalator, and when that person moves off the escalator, pass detection switch: 1 turns ON, and the illumination lamp and escalator return to a non-operating state.
In this example, consider both pass detection switches: 0 and 1 as non-hold type switches. Another assumption in this example is that people do not continue to get on this escalator.
Input Pass detection switch:0 X001 Pass detection switch: 1 X003 Output Illumination lamp Y000 Escalator drive output Y003
When input X001 is turned ON, outputs Y000 and Y003 operate. Next, when input X003 is turned ON, outputs Y000 and Y003 become non-operational.