tower cranes

Thread Starter

nimanik

Joined Dec 22, 2011
10
now a day this crane controlled by PLC and i have not found the existing boards and instruments in it's cabinets used before but i think it consist switches conductors relays and circuit brakers
one cabinets for supplying power and one of them for driving and maybe one for protecting
 

strantor

Joined Oct 3, 2010
5,369
Well I think that the hydraulic parts can not be removed, but how can i protect it's motors against overload i mean how can i input the charactrisics curves of a motor to a PLC ,can a PLC like " logo" sense the overload by it self?

after that can PLC braek the current and open the circuit by it self or it's output should be given to a circuit brakers or conductors?

as i know this kind of cranes need at least 3 motors one for hoisting, one for slewing and one for trolling if each of this motors have to drive diffrently simultaneously can a LOGO drive them at the same time?
If the crane is already hydraulic, there's no reason to remove the hydraulics. they work perfectly well, especially when the ramp rates are controlled and tuned well. Makes for a smooth operation. It is not typically the job of a PLC to detect motor overcurrent or protect motors in any way. There are motor control/protection devices specifically designed for this. Google "motor starter" - there are both hardware and solid state options. Now, if you plan to replace hydraulics with motors, then the VFDs will provide the overcurrent protection.
 

strantor

Joined Oct 3, 2010
5,369
now a day this crane controlled by PLC and i have not found the existing boards and instruments in it's cabinets used before but i think it consist switches conductors relays and circuit brakers
one cabinets for supplying power and one of them for driving and maybe one for protecting
take pics of the cabinets inside and post them. post the model #s of what's in there
 

strantor

Joined Oct 3, 2010
5,369
I'm confused now. I originally thought you just wanted ideas on how a PLC works in a crane. Then it sounded like you had a crane that you intended to install a PLC in. Now it sounds like you've never seen a crane, and are posting pics of random electrical cabinets. So, what is it? Are you upgrading a crane to PLC control for your project? or are simply asking how does a PLC work in a crane?
 

Thread Starter

nimanik

Joined Dec 22, 2011
10
i've seen crane but not it's cabinets and i don't know what each of it's cabinet does i know how to move crane with PLC but it's pictures are so confusing and i want to know what each part of it does
 

spinnaker

Joined Oct 29, 2009
7,835
i've seen crane but not it's cabinets and i don't know what each of it's cabinet does i know how to move crane with PLC but it's pictures are so confusing and i want to know what each part of it does
So you have never seen the control cabinets of one of these cranes. You know nothing about them. But somehow you think you are going to be able to learn enough information via a forum to redesign the cabinets?

You do realize there are whole teams of people with years of education and experience in design that design these controls?

How do you expect to do better than them from the little bits of information that you learn on a forum?
 

strantor

Joined Oct 3, 2010
5,369
i've seen crane but not it's cabinets and i don't know what each of it's cabinet does i know how to move crane with PLC but it's pictures are so confusing and i want to know what each part of it does
Ok I still do not know what you want. Are you talking about a specific crane? You say you want to know what each part of the crane does; well, that depends on the crane. Some cranes have parts that other cranes don't have. You showed a cabinet with a bunch of contactors in it. I have no idea what each contactor does, as I've not seen the crane. please, in sufficient detail, say exactly what you would like to know. For example "my crane is purely hydraulic/mechanical. All functions (up/down/left/right/in/out/clamp/unclamp) directly controlled by hydraulic hand lever valves. I would like to know how to automate these functions with a PLC." - and I really hope that this isn't your question. I still don't even know if your crane is hydraulic, or even if you have a specific crane in mind.
 

Thread Starter

nimanik

Joined Dec 22, 2011
10
the cabinets i've shown are for a tower crane i don't know if it's for a new one controlled with PLC or not but many of the old tower cranes don't have PLC part they only controlled and protected with electrical instruments what i want is how can make that old tower cranes to a new one don't need those many electrical protection parts in fact i want the steps of becoming those old tower cranes to new
 

strantor

Joined Oct 3, 2010
5,369
the cabinets i've shown are for a tower crane i don't know if it's for a new one controlled with PLC or not but many of the old tower cranes don't have PLC part they only controlled and protected with electrical instruments what i want is how can make that old tower cranes to a new one don't need those many electrical protection parts in fact i want the steps of becoming those old tower cranes to new
ok, I will assume that the old tower cranes are hydraulic.
so, you would need to replace the old manual levers with proportional valves & install proportional valve controllers.
look into replacing whatever motor protections with these (size 1 solid state overload relay, that has class trip function, phase loss, ground fault,5.5-22 amp range adjustable), sized appropriately.
Install a PLC with enough analog outputs to run all your valve controllers (or valve contrllers may have serial interface).
Install a joystick for manual control
Install encoders to measure traverse distances and position
run these inputs to PLC and program the PLC to recognize positions (x,y)
Install HMI, network with PLC. Design HMI interface with homing position and position input so you can type coordinates in and autmatically crane moves to the position.
install encoder on the winch in same manner for the crane to go to specified height.
tune all the ramp functions so that the crane is not jerky
program avoidance areas so that the crane does not crash into things.
program safety features, such as a loud horn that goes off for 10sec before the crane can move, and then stay on while the crane is moving. Also a low fluid level safe shutdown.
remember to design fail safe, all valves spring return to blocked position; in the case of a power outage you don't want the crane running away or dropping payload.
Remember to install emergency stop pushbuttons EVERYWHERE. Anyone, at any time, should be able to stop the crane.
Install a loadspeaker.
install a cupholder.
done.
 
Top