Simple expandable Goods Elevator control syste

[prashanth58]

I have an urgent req of executing a goods lift from two floors to say about 15 floors with provision for higher and lower floors also. I hv executed a GL for a single floor using two 2p2w relays wired as latches, and one 2p2w wired as stop/reset which is working very reliably using 12v wiper motor along with the worm drive driving a white rope drum with the whole thing having limit s/w at either end. Req here are carriage floor position indicators. Up Dn indicators. Mandatory 10 or 15 sec hold after which a buzzer in lift carriage will sound for about a min b4 shutting off. As it's a simple lift there will be no gate management as such. My req for the above is limited to the (expandable) control unit that directed the lift to move up/down or no action if its on the same floor as I'm pretty familiar with the rest of the "bells& whistles". Your close cooperation from knowledgeable members will be deeply appreciated. Thanking you. prashanth58in@gmail.com

 

[rjenkinsgb]

Although it is technically possible to create such a system with only electromechanical components, that is extremely complex and expensive.

Using a PLC (Programmable logic controller) would be the most economical approach.

It will also need multiple switches at each floor position for levelling and centring.


With a gate or door interlock system, I'm not willing to provide further information - if any kind of injury is possible due to lack of interlocking & safety devices, anyone working on it could be legally liable for any injury.

[If it can transport any practical weight of "goods", it's powerful enough to amputate fingers if not larger limbs. By UK & European law, that needs doors or gates, either with double loop guard controls to ensure they are closed before anything can move, or a double loop & self-monitoring emergency stop system. I'm in the UK so I have to abide by those regulations].

 

[tepalia02]

Although it is technically possible to create such a system with only electromechanical components, that is extremely complex and expensive.

Using a PLC (Programmable logic controller) would be the most economical approach.

It will also need multiple switches at each floor position for levelling and centring.


With a gate or door interlock system, I'm not willing to provide further information - if any kind of injury is possible due to lack of interlocking & safety devices, anyone working on it could be legally liable for any injury.

[If it can transport any practical weight of "goods", it's powerful enough to amputate fingers if not larger limbs. By UK & European law, that needs doors or gates, either with double loop guard controls to ensure they are closed before anything can move, or a double loop & self-monitoring emergency stop system. I'm in the UK so I have to abide by those regulations].

Sir, is it possible to implement such a system with a Raspberry pi?

 

[rjenkinsgb]

Sir, is it possible to implement such a system with a Raspberry pi?

Possible, yes - with a lot of additional inputs & circuitry to work with higher voltage signals (eg. 24V) plus noise and spike protection; and then output relay drivers to control things.

It quickly becomes very complex and an expandable PLC is almost certainly more practical & likely to be more reliable for an application such as that.

(Using 3.3V or 5V signals through switches is unreliable once they start to oxidise, plus the wiring will be extremely sensitive to interference and spikes, which can cause false input signals or damage device inputs. 24V is enough to "wet" normal switch contacts, which is why it's used as an industry standard for control gear).


The safety circuits for guarding or emergency stop must be a totally separate system that can override the electronics and shut things down to be compliant with safety regulations, and that itself has legal requirements, eg. double loop and self-testing, where serious (lasting or permanent effect) injuries are possible.

If the OP is in India, the regulations mentioned in this article would apply:

Machinery Safety Standards in INDIA | Machine Guarding

Machinery Safety Standards in India Machine guarding IS 16813 , IS 16814, IS 16815 , IS 16810 , Minimum Gap reuirment in guarding

machineguarding.in

 

[Nigel Goodwin]

We used to have a small goods lift where I used to work, essentially for taking TV's upstairs, it was only ground floor and first floor - if I recall it was rated at 1.5cwt?.

When it was originally put in (well before my time), it was completely open, and when upstairs it could be wheeled along a ceiling mounted girder, into the TV stock room, for easy unloading

However, before I started that had been banned, and it had to be all cased in, and not allowed to be run along the ceiling.

Because it was boxed in, it then became a 'lift' and not a 'hoist', and so became susceptible to the same regular inspections as 'people' lifts.

However, as it was so simple the requirements it had to meet were extremely low - there was just a switch on each door, which stopped it working unless both doors were closed, and limit switches that supposedly stopped it at the correct place at the top and bottom. There was no electronics at all, just switches on the two doors, top and bottom limit switches on the cable drum, up and down buttons at top and bottom (you simply held the button down until it stopped on the relevant limit switch), and a solenoid operated drum brake.

Nothing like modern requirements for a multi-floor lift though.

I would agree that PLC's would be the way for the OP to go.