# 5 Stop cable car



## simmo (Dec 12, 2007)

Hi guys,
I work for a company that manufactures rail cable cars in residential properties. (basically the garage is at street level and house is usually down the side of a cliff on the waterfront) that type of scenario anyway. So we make and install these inclinators that make access to the home possible without the countless steps. I'm currently working on a property that has five levels of stopping stations.

This is a first for me with this amount, usually they are just two stops (top and bottom) 

The control is using a SEW motor speed controller (VSD), Allen Bladley Micro logix PLC, and an Encoder mounted on the output shaft of the winch to make the count at the landing levels, and all the commands are through a Pheonix RF controller with 4 channels plus extra input and output module to make up the required amount of I/O's necessary. What has me stumped is that on every station I need to integrate landing level gate lock outs. This is necessary so that people dont just open the gate and step out when no cable car is at that level.

Any ideas on how this can be achieved?
I'm kind of thinking that once the drive has ramped down and stopped at the level the car has been called to, the Encoder could signal the PLC to give an output for an Electric door strike on the landing level to go closed circuit, through a relay, but I don't really want the door strike to time out and go open circuit again until the door on the car has been shut, as it has been actuated by the door limit switch. 

I hope all this makes some sense.


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## Introyble (Jul 10, 2010)

simmo said:


> Hi guys,
> I work for a company that manufactures rail cable cars in residential properties. (basically the garage is at street level and house is usually down the side of a cliff on the waterfront) that type of scenario anyway. So we make and install these inclinators that make access to the home possible without the countless steps. I'm currently working on a property that has five levels of stopping stations.
> 
> This is a first for me with this amount, usually they are just two stops (top and bottom)
> ...


When an elevator is running, the car door is locked in the closed position by a brake shoe which engages the edge of the door hanger in response to a push-type solenoid overcoming the force of a spring. When the door is not closed, a friction brake pad contacts the door hanger surface to hold the door open for passenger boarding or to stop the door in case of failure of door operator power while the door is in motion.


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## simmo (Dec 12, 2007)

This is not an Elevator in the sense of a Lift. No tapered sliding blocks to act as a brake on the rails. The brake control is Electric brake motor and a mechanical brake by means of a clutch arrangement that operates if speed exceeds .75 metres/sec. It throws out a cam to release a spring and a locking device drives hard onto the rail.

This should give a better idea of the lift in question.


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## micromind (Aug 11, 2007)

One fairly simple solution would be proximity switches at each gate that would energize an unlocking mechanism only when the car is present.


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## Introyble (Jul 10, 2010)

micromind said:


> One fairly simple solution would be proximity switches at each gate that would energize an unlocking mechanism only when the car is present.


Yeah, that looks like a wild ride. I think I would sit on the trip down


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## Introyble (Jul 10, 2010)

simmo said:


> Hi guys,
> I work for a company that manufactures rail cable cars in residential properties. (basically the garage is at street level and house is usually down the side of a cliff on the waterfront) that type of scenario anyway. So we make and install these inclinators that make access to the home possible without the countless steps. I'm currently working on a property that has five levels of stopping stations.
> 
> This is a first for me with this amount, usually they are just two stops (top and bottom)
> ...


you couldn't totalize (record) the encoder pulses to latch/unlatch for various values?


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## simmo (Dec 12, 2007)

Introyble said:


> you couldn't totalize (record) the encoder pulses to latch/unlatch for various values?


I don't know if that is possible or not? How would this be achieved on the Micro-Logix, never seen this function, but willing to try anything - so I'm happy to learn.

One thing I will point out, there are limit switches at the Top and Bottom of the rail. At the very top is the Extreme overrun limit, below that is the Top limit, and about 3 metres down the rail is the Home limit. This limit switch is the set point for the count of the Encoder. At the very bottom of the rail is the Bottom limit which is in place before the rubber buffer.
All the counts of the Encoder are taken from the Home limit switch for the values. We actually can control the car to ramp up and down at various points on the rail (ie; changes in the transition of incline, or going around a bend in the rail) so I guess recording values isn't an issue, because we do this anyway for what I've just explained, but hows it possible to latch/unlatch an output off the count if the car is at level five and it's called for at level two. Would levels four and three have the landing gates open as the car passes them at each of those levels from the Encoder count? I don't want that to happen. I only want the gate at the level the car is called to, to go un-latched. It's easy if only two stops are in place as the count will only un-latch at either end. Plus the Top and Bottom limits if actuated will stop the drive as part of the safety circuit and the gates will go closed circuit and allow exit from the car in the event of an emergency exit. The only other reason the gates would un-latch is if the Slack rope limit switch is applied, meaning the wire rope from the winch has gone past the Bottom limit switch, or the rope has broken.


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## micromind (Aug 11, 2007)

A time delay would prevent the doors from opening while the car travels through, but would allow them to open if the car is stationary long enough.


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## s.kelly (Mar 20, 2009)

micromind said:


> A time delay would prevent the doors from opening while the car travels through, but would allow them to open if the car is stationary long enough.


That could present a dangerous situation if the car stopped other than in the landing. Definately could be an issue if this lift falls in elevator codes and listings, which I think it should.

I used to install similar lifts and a prox. or cam set up is typical in what I installed. Guess I remember mechanical cams that open the stations most often, but I am sure there are other ways to make it happen.


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## AussieApprentice (Aug 16, 2008)

I would not rely on the encoding to know when it is safe to open the landing doors. If there is an error in the encoder then the car coul be anywhere.

All lifts I have worked on have a mechanical interface between the car and the landing door which opens or unlocks the landing door. On the basic systems you are familiar with, how is the upper landing door unlocked?


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## Southeast Power (Jan 18, 2009)

AussieApprentice said:


> I would not rely on the encoding to know when it is safe to open the landing doors. If there is an error in the encoder then the car coul be anywhere.
> 
> All lifts I have worked on have a mechanical interface between the car and the landing door which opens or unlocks the landing door. On the basic systems you are familiar with, how is the upper landing door unlocked?


Im sure you Blokes have design professionals, manufacturers and local ordnances with very specific component and installation requirements. 

For some reason, all I could think of was the Saturday Night Live skit back in the 70s called "Ask President Carter"

http://www.nbc.com/saturday-night-live/video/ask-president-carter/278764/?__cid=thefilter






.


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## John Valdes (May 17, 2007)

If this lift is UL approved, use the mechanisms that are listed for the equipment.


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## micromind (Aug 11, 2007)

s.kelly said:


> That could present a dangerous situation if the car stopped other than in the landing. Definately could be an issue if this lift falls in elevator codes and listings, which I think it should.
> 
> I used to install similar lifts and a prox. or cam set up is typical in what I installed. Guess I remember mechanical cams that open the stations most often, but I am sure there are other ways to make it happen.


Where is the danger? In my scheme, two things would need to happen in order for the doors to open.

1) The car is properly docked at any one of the loading stations. This is determined by proximity sensors only, not an encoder. The sensors can be either electronic or preferably, mechanical.

2) The car is in the dock for slightly longer than it takes it to travel through the dock, and it is not moving.

This system can be either so complicated that it very likely won't work, or it can be very simple, and thus, reliable.


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## s.kelly (Mar 20, 2009)

Micro, you are right, reading again in the daylight I must have misread your post, even though I quoted it. The set up you describe does not sound like one that could open the door at a bad spot.


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## simmo (Dec 12, 2007)

AussieApprentice said:


> I would not rely on the encoding to know when it is safe to open the landing doors. If there is an error in the encoder then the car coul be anywhere.
> 
> All lifts I have worked on have a mechanical interface between the car and the landing door which opens or unlocks the landing door. On the basic systems you are familiar with, how is the upper landing door unlocked?


This is not an ordinary lift though - It's called a Railglider Cable car.
I've worked it out today and if I'm right all will be sweet. I going to try and wire this using the pulse from the encoder to give a signal on an output of the PLC to the VSD.

So in theory - This is how I hope it will work
The car is at level 5 and it's called for at level 2 for example.
Car travels down the rail past levels 4 and 3.
As it approaches level 2 it starts to ramp down on the Drive, as set up by the encoder count until stopped at level 2.
The Drive will apply the electric brake control, this will give me a 24 volt DC output from the brake coil for my power up to the door strike on the landing gate (Power on to release) Once the people have entered the car and shut the door on the car, the safety circuit is again secure, by the car door limit switch going closed, and when the Send push button from within the car is pressed, it lifts the brake and the Drive starts up again. As soon as the brake is released so is the power to the door strike on the landing gate.

The landing gate door lock will only open at the level it is called to (once the Drive has stopped and brake is energised) because the PLC knows where the count is by which level the car is called to. No other gates will open at any other level.

I'm hoping I have enough conductors in the 18 core cable I have inside the rail, as I use 12 for the call stations and I will need a common positive plus a negative and each level for the door strike.
Each call station has as pictured an LED Indicator, a Call button, an Emergency stop and a Keyswitch.


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## simmo (Dec 12, 2007)

John Valdes said:


> If this lift is UL approved, use the mechanisms that are listed for the equipment.


We manufacture the equipment and site install it.
The Railcar code in Australia is actually the New Zealand code for regulations and safety. There are no specifics on how it goes together and what components to use, just as long as the required regulations meet the code and all are in use, and functioning.


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## Fredman (Dec 2, 2008)

simmo said:


> *We manufacture the equipment and site install it*.
> The Railcar code in Australia is actually the New Zealand code for regulations and safety. *There are no specifics on how it goes together and what components to use*, just as long as the required regulations meet the code and all are in use, and functioning.


:001_huh:




That's just does not sound right or safe. :no:


My 2 cents.


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## John (Jan 22, 2007)

Try looking onto one of these switches.

http://www.clrwtr.com/IDEC-Interlock-Switches.htm

I have used them to prevent opening the doors on machines before the machine has stopped running.


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## simmo (Dec 12, 2007)

John said:


> Try looking onto one of these switches.
> 
> http://www.clrwtr.com/IDEC-Interlock-Switches.htm
> 
> I have used them to prevent opening the doors on machines before the machine has stopped running.


 
Yes - I know the switches, but they don't lock the door or gate in my application physically.


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## simmo (Dec 12, 2007)

Fredman said:


> :001_huh:
> 
> 
> 
> ...


 
If you look at the photos I've posted, clearly you can see these Rail cars are extremely well made, Engineered to the highest quality in every respect. They are self levelling on any incline. The sales for them exceed what we can manufacture and install. The NZ code is very specific about the safety requirements of them, they just do not say you must use this brand of controller, or this motor/gearbox, or that brand of limit switch -that type of thing.

Watch this video, This is from the company I work for.
http://www.youtube.com/watch?v=yFr16nTpo88


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## MDShunk (Jan 7, 2007)

Do what you want, but counting encoder pulses and assuming that the car is actually where you think it is seems like a risky and dumb idea. Encoders fail and encoders miss pulses. That car could be anywhere, and going by the encoder alone isn't something I'd be comfortable with. 

In the US, an elevator car physically presses in mechanical mechanisms to allow the door to open. Something mechanical would be my first choice, and a prox switch (probably 2 of them) would be my second choice.


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## Bob Badger (Apr 19, 2009)

MDShunk said:


> Do what you want, but counting encoder pulses and assuming that the car is actually where you think it is seems like a risky and dumb idea. Encoders fail and encoders miss pulses. That car could be anywhere, and going by the encoder alone isn't something I'd be comfortable with.
> 
> In the US, an elevator car physically presses in mechanical mechanisms to allow the door to open. Something mechanical would be my first choice, and a prox switch (probably 2 of them) would be my second choice.


Ditto that.

Back in my 'carny' days encoders would be used for somethings but always backed up with real switches of some type. 

Ever see a 200 HP DC motor connected to literally tons of chain try to go back and forth from full reverse to forward with no decelerate / accelerate time.  

I have, it was noisy and it was scaring the F out of all of us until it jerked a counterweight up against a safety switch in the e-stop circuit. It was traced back to a bad board in the drive that read the encoder signal.


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## simmo (Dec 12, 2007)

MDShunk said:


> Do what you want, but counting encoder pulses and assuming that the car is actually where you think it is seems like a risky and dumb idea. Encoders fail and encoders miss pulses. That car could be anywhere, and going by the encoder alone isn't something I'd be comfortable with.
> 
> In the US, an elevator car physically presses in mechanical mechanisms to allow the door to open. Something mechanical would be my first choice, and a prox switch (probably 2 of them) would be my second choice.


 
Don't shoot the messenger, I don't design the Electrical circuits, we have an Electrical Engineer for that - A former Otis Elevators engineer with 35 yrs designing the circuits. I have spoken with him today as he is based in Adelaide and I am in Sydney, so in this particular residence where this railcar is installed, he was un-aware that landing gates were required. Part of the code states that if the landing level is less than 1.0 metre to the ground - then gate lockout is not required. In this instance the levels are over 1.0 metre so he is making the changes to the schematics for me. 

Just on the subject of things failing ie: Encoders missing counts etc, Is it not possible for a proxy to not detect an object in front of it, or a limit switch to fail through bad or corroded contacts?

Anything can fail, so that statement falls a little short in my book.

On a final note, there are over 250 of these things operating in New Zealand and 130 here in Australia. I have not heard of a single problem relating to the encoders as a direct form of a fault. I have had situations where limit switches have failed, usually at the very bottom of the rail where they are mostly exposed to sea spray and salt, as these things are usually installed with waterfront properties.


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## MDShunk (Jan 7, 2007)

simmo said:


> Don't shoot the messenger, I don't design the Electrical circuits, we have an Electrical Engineer for that - A former Otis Elevators engineer with 35 yrs designing the circuits. I have spoken with him today as he is based in Adelaide and I am in Sydney, so in this particular residence where this railcar is installed, he was un-aware that landing gates were required. Part of the code states that if the landing level is less than 1.0 metre to the ground - then gate lockout is not required. In this instance the levels are over 1.0 metre so he is making the changes to the schematics for me.
> 
> Just on the subject of things failing ie: Encoders missing counts etc, Is it not possible for a proxy to not detect an object in front of it, or a limit switch to fail through bad or corroded contacts?
> 
> ...


All true, which is why I push first for a mechanical means for the car to unlock the gate. Like, the car being physicallly present to press a latch, much like elevator cars do for the door.


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## AussieApprentice (Aug 16, 2008)

Fredman said:


> :001_huh:
> 
> 
> 
> ...


I can't think of any of our standards that are set up any other way. Even our AS3000 wiring rules don't specify what products must be used. You may use any product that meets the specified requirements.


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## simmo (Dec 12, 2007)

MDShunk said:


> All true, which is why I push first for a mechanical means for the car to unlock the gate. Like, the car being physicallly present to press a latch, much like elevator cars do for the door.


All very true - "but I quote" this is not a vertical elevator, it does not have light curtains for door entry and exit either. In fact - it does not share much of the safety elements that go in an elevator. It does not have counter-weights like an elevator needs. This is just a simple winch driven from a reduction gearbox via a VSD.
I guess this may seem a little hard to fully appreciate without having seen one of these Railcars in motion, and for an Electrician at least to understand the control unless he can see the electrical schematic of it.
Anyway thanks for everyones input, I'll see what our Engineer comes up with in the next day or two.


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## simmo (Dec 12, 2007)

AussieApprentice said:


> I can't think of any of our standards that are set up any other way. Even our AS3000 wiring rules don't specify what products must be used. You may use any product that meets the specified requirements.


 
AussieApprentice - that should be AS/NZ3000 wiring rules (Part of the Trans Tasman agreement. LOL


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