### Plc Program

greenspun.com : LUSENET : Elevator Problem Discussion : One Thread

I need help to write a plc program on lifts. I am currently given a project by my teacher to write a plc program which will help in reducing time taken for two or more lifts to arrive at the floor where the up or down button has been pressed. What should i consider for this type of program? And if its possible can anyone pls send me a flow chart?

-- Michael Moe (topol_m2003@yahoo.com), September 01, 2003

Here's a partial list of elements to consider: - Direction of travel and distance of the lifts from the call (distance to travel, to be more precise, since the lift may have to travel away before coming back) - Other registered hall calls to distribute, and registered car calls in each lift (each adds 10 to 15 seconds of travel time) - Coincident car and hall calls (i.e. on the same floor in the same direction, which can reduce the number of necessary stops) Basically you must estimate the time each lift will take to reach each hall call, temporarily allocate the calls to lifts, and repeat the process as often as you can, because the conditions stated above change continuously. At one point though you have to decide to not change an allocation anymore because a lift is at the critical point where it must decelerate or continue its route (the lift usually sends that information). Also, don't necessarily give a hall call to the first lift to come by. You could for example consider to let a lift bypass a hall call to answer another one if a second lift can answer the bypassed call in a reasonable time (and as a bonus has a car call for the same floor). In other words don't necessarily treat each hall individually, rather as a group that deserves more or less equal treatment. Big elevator companies have doctors in mathematics to create equations to solve these problems. In spite of what I said, don't try to make it too complicated for your project, especially that a PLC is far from the ideal platform to implement that. Good luck! JL

-- JL (j.laro@sympatico.ca), September 01, 2003.

Hey Mike I am curious what type of school has this as an assignment, also what plc are you using. Jim

-- JIm (elevator555@hotmail.com), September 01, 2003.

National University of Sing and the plc is Omron.

-- (topol_m2003@yahoo.com), September 02, 2003.

Hey Mike Is That Singapore you are refering to, If it is I used to work there. Jim

-- Jim (elevator555@hotmail.com), September 03, 2003.