How elevators work???

@strongheart THAT IS HILARIOUS!

The new elevators you do not press up/down but your desired floor.  You are then instructed to the designated lift.

In my building when both elevators were working, sometimes both would arrive simultaneously.  This seems like a waste of energy - bad programming.

@strongheart Not necessarily. It depends on the time of day. Even pre computer days, a clock was available to pre-condition the relay logic as follows.

This is for a office building.

In the morning, if a car was unoccupied and not being otherwise signalled, it goes to the bottom floor because statistically at that time more people are arriving than leaving or moving between floors.

Similarly at close of business the default position for an empty non-busy car is the top floor.

In between those hours several possibilities exist, one at top one at bottom, both in middle, leave at last floor visited for x amount of time were all algorithms I saw. If the building had enough daytime visitors then favouring the top and bottom floors was the norm. If it was more of a commercial business with few visitors then the middle or last floor visited was the preferred approach. All that can be done with relays.

@strongheart I just noticed there is a second point to your question. In elevators with floor selection exteriour to the cab then some modifications are possible. If for instance in a multi elevator environment we see a pre-programmed number of floor requests then 2 or more cabs can be dispatched to the calling floor to pick up passengers. It is also possible they are timed to arrive simultaneously in order to spread the load. In cases of enough banks that cars are on both sides of a common foyer then a slight delay based on how many buttons were pressed on that wall vs the other. I don't know if every possible scenario was covered, but they were much more sophisticated in the logic than the average person is ever aware of.

Posted by: @zander

@inst-tech I am always intrigued by my American friends who actually know people who have had their home's broken into. I live in Canada, and I don't know a single person this has happened to and other than one case (me) of a joy ride of a couple hours do not know of anyone who has had a car stolen. One of my former work associates from NJ had her car stolen 5 times in a couple months.

Yes, and there is a big reason for that.. First thing, our countries are physically the size size in land mass, about 9 million sq km, but population wise, America is 331 million, almost 10 times Canada's population of 37.9 million. So the point is.. population density .. Whenever you have people packed densely , especially if they are from many different ethnicity, cultures, and all the different languages & dialects that go with it, you are sure to have a lot of social problems. So, no... I'm not surprised in the least that you haven't experienced those types of criminal elements.. As a matter of fact, I'm quite pleased that your country is not plague by that particular crime..Although you seemed to have bigger fish to fry politically as we do..

Well, enough of my sermon of the day on population density and the like.. back to the topic at hand..

regards,

LouisR

Posted by: @strongheart

@inst-tech Back in the day when you could dial zero for an operator and ask her what time it was, one operator had a call sometime before Noon every day, usually 11:55 and he'd ask her what the exact time was. 
Well after about a year she finally asked, "You've been calling me every day just before noon, why do you do that?"
"I'm the fire chief and I need to know the exact time so I can blow the noon whistle."
"Oh wow, I set my watch by that whistle"

How can things fgo wrong here?

 

 

Hilarious... but probably true..lol   Indeed, what could go wrong!...

Most of my problems with the alarm were with my wife forgetting the combination and setting it off...lol

Eventually, I had to disarm it..and buy a dog!  lol

Regards,

LouisR

@zander

More sophisticate and expensive elevators stopped slowly but older cheaper stopped hard.

They can accelerate gradually up to very high speeds and then gradually deaccelerate to a stop so you really don't have much sense of moving at all. Maybe a little bit of PID control involved.

@zander My Uncle had a furniture store with an old 2 storey elevator in the warehouse in Patterson, NJ.  A lever for up-down. 
Had to get the level right manually.   

I was young, I can recall elevator operators, but most were "modernized".

My friend's daughter lived in Yonkers for a bit, directly across from the original Otis Elevator company.
In afterthought, I should have stopped in.