Author Topic: Elevator Position Sensor  (Read 447 times)

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Offline fuquar7

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Elevator Position Sensor
« on: May 16, 2019, 02:08:30 am »
I have a 4 stop hydraulic elevator installed in 1955 that has not modernized.
I am looking for ideas to do two things.

1) auto park the elevator at its lowest level after a set wait time and or after a certain time of day
2) have a position/direction indicator

I want to use an Arduino with a real time clock. The auto park is the easy part, I am having trouble figuring out how to setup a position sensor of some kind. The elevator controller runs all switching/relays at 120 VAC
 

Online ejeffrey

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Re: Elevator Position Sensor
« Reply #1 on: May 16, 2019, 03:01:00 am »
I would try a laser tape measure.  You can buy them cheap and I am sure there are videos on tearing them down and connecting an arduino.  Its possible that the sensors are available from places like sparkfun ready to integrate as well.
 

Offline pwlps

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Re: Elevator Position Sensor
« Reply #2 on: May 16, 2019, 03:15:08 am »
I would look for a laser rangefinder with analog or RS232 output.
There are plenty of those on Alibaba  for example https://www.alibaba.com/product-detail/50m-high-precision-laser-sensor-to_60622103739.html?spm=a2700.7724857.normalList.7.5bfb3be2FQxCl1&s=p
Otherwise try to hook up an analog output from a hanheld rangefinder ?
 

Online Tom45

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Re: Elevator Position Sensor
« Reply #3 on: May 16, 2019, 03:31:34 am »
If the elevator position control is closed loop, there must already be some kind of position feedback available. You could try to use that.

In 1969 I worked in a new 4 story office building with a hydraulic elevator. After sitting idle all night, it was sluggish enough that it would often not quite make it to a floor. It seemed to stop close but then could take minutes to creep the last little bit into position and open the door. So the first person to arrive in the morning would send it to the top floor, but exit before the door closed and take the stairs to the second floor. After one or two 1st to 4th round trips it was good to go for the day.
 

Offline ucanel

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Re: Elevator Position Sensor
« Reply #4 on: May 16, 2019, 03:33:03 am »
Elevators has very serious regulations.
Latest one in our country is EN 81-20
i have worked in a company that produces
elevator controller cards and its all other components,
my job was the designing the pcbs and
writing the programs according to the standards
as a part of a team.

If you want to take the responsibilities
you can make modifications
but i do not recommend this.

As a sensor commonly used one is named
bistable and monostable sensor
it is a hall effect sensor
you have the magnets at the pit
2 for each floor level
1 for door preopening space and
1 up and 1 down slowing level indicator
and sensors at the cabinet.

There is also different layouts for sensor magnet positioning.

 
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Offline fuquar7

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Re: Elevator Position Sensor
« Reply #5 on: May 16, 2019, 06:44:34 am »
In my area elevators are regulated by ASME A17.1-2016, work is to be carried out by an ASME certified tech or elevator owner per state law.
I don't want to get into the wiring of the elevator to much other than the call button for the lowest floor I have the original schematic and everything is very well labeled/tagged.

I think the hall effect sensor is the best route since I will not interfere with the operation and wiring of the elevator as is.
The arduino sketch would be rather easy I believe.

The elevator consistently levels correctly at each floor (does not vary more than 0.25" no matter the weight in it) which I think the sensors would be able to deal with.

I have to order up some sensors and I will keep everyone posted on what I manage to come up with.
 

Offline OM222O

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Re: Elevator Position Sensor
« Reply #6 on: May 16, 2019, 07:12:04 am »
Elevators has very serious regulations.
Latest one in our country is EN 81-20
i have worked in a company that produces
elevator controller cards and its all other components,
my job was the designing the pcbs and
writing the programs according to the standards
as a part of a team.

If you want to take the responsibilities
you can make modifications
but i do not recommend this.

As a sensor commonly used one is named
bistable and monostable sensor
it is a hall effect sensor
you have the magnets at the pit
2 for each floor level
1 for door preopening space and
1 up and 1 down slowing level indicator
and sensors at the cabinet.

There is also different layouts for sensor magnet positioning.



I second this. Elevators are not something to mess with, even if you're a skilled electrician / electronics engineer. there are strict safety rules meant to protect you. I would advise having a contractor to modernize / replace it for you. especially after reading your post about using an arduino. THEY ARE NOT INDUSTRIAL PARTS. they can glitch out all the time. even if you want to use a MCU, choose an automotive one with certifications for similar applications. T.I usually mentions these sorts of things but I haven't used other manufacturers and they probably have similar offerings.
« Last Edit: May 16, 2019, 07:15:31 am by OM222O »
 

Offline amyk

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Re: Elevator Position Sensor
« Reply #7 on: May 16, 2019, 11:48:16 am »
Relax, I don't think he's actually modifying the actual elevator components but looking for an add-on. However I wouldn't recommend an Arduino either. ;)

What type of position are you after? If you just want to know to the nearest floor, I'm pretty sure the existing system will have those sensors already.

As much as this is an electronics forum, I'd go with something simpler and probably without an MCU --- after all, the original design worked for over half a century already, and will probably continue to work for another 50 years given regular maintenance.
 

Online ejeffrey

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Re: Elevator Position Sensor
« Reply #8 on: May 16, 2019, 01:06:06 pm »
Elevators has very serious regulations.

That is why I recommended a non-contact external mechanism like a laser time of flight sensor.  That way you don't have to interface with or modify the actual elevator at all.
 

Offline fuquar7

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Re: Elevator Position Sensor
« Reply #9 on: May 16, 2019, 01:31:02 pm »
The only thing that will be added to the wiring of the elevator is relay to call the car to the basement. I am even contemplating an actuator to push the button in the control room, that way I do not alter the elevators designed function.

I will only be adding sensors and display to show the cars current position and which direction it is currently moving. all independent of the original wiring. Modernization is upwards of $70,000 USD possibly more if the jack has to be replaced ($20,000 installed)
 

Offline floobydust

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Re: Elevator Position Sensor
« Reply #10 on: May 16, 2019, 02:01:05 pm »
Does it have any kind of electric motor drive? I worked on one elevator with an SCR drive and the EMI from the phase-control filled the building with hash and interference.
One position sensor was an encoder on the big top floor cable spool.
Hydraulic cylinder, it must already have position sensors?

You could just use a timer relay; After x minutes of no use/movement, autopark.
 

Offline ucanel

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Re: Elevator Position Sensor
« Reply #11 on: May 17, 2019, 03:40:41 am »
I am stricly oppose to use or even thinking about to use arduino toy for these kind of serious jobs.

If you were seen us at the compliance test
you would think exactly like i said.
And i recommend you to watch some elevator accidents
before attempting to do anything.
One other thing
regulations put you to do place that you can imprisoned because of your unauthorized actions,
i do not add the moral responsibilities that you will encounter
any possible accidents caused by your modifications.

I would like to help if you just want to make taught experiments.
 


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