Hello, everyone

[Deyan Tenev]

Sorry for my question, someone will say its stupid, but this is my first time that i try to programing PLC controller.

I have V700 and i fix everything , but now here is my problem:

I need to control a crane , to stop on different positions , which are selected before switching in automatic mode.

Can someone help me whit any ideas how to configure this in my ladder?

 

[kratmel]

I think this crane

5 hours ago, Deyan Tenev said:

 stop on different positions , which are selected before switching in automatic mode.

is the same task as elevator PLC control.

Please read this info about ladder logic idea

https://instrumentationtools.com/elevator-plc-ladder-logic/

https://www.theseus.fi/bitstream/handle/10024/338304/PLC Controlling Program of an Elevator_Thai_Nguyen.pdf?sequence=5

https://www.ijser.org/researchpaper/Implementation-of-a-Four-Floor-Programmable-Logic-Controlled-Elevator-System.pdf

You can find different control strategy for elevator ("vertical crane") and try to build your own code.

[Deyan Tenev]

Thanks for ideas, and yes - normally is "vertical crane".

I check this links that you send me,  but the other problem is - I have only one NPN sensor, witch is positioned on the crane. The elevator have much more sensors.

[kratmel]

In general, the main problem in your case is to calculate the position of the crane.

I'm afraid that it is almost impossible to do this clearly with the help of one sensor.

Therefore, I recommend reading the information about the quadrature signal and using two sensors on the crane to distinguish the direction of movement and count the positions as a number. Accordingly, you will avoid vibrations and false readings of the position counter.

In the PLC, it is possible to use two high-speed inputs as an encoder input and automatically count the positions of the crane, which must be marked by the corresponding mechanical fixed parts from which the two sensors can read the signal.

Another problem is to set the zero position after switching on. But in general, the main thing is to calculate the positions correctly - and with the help of only one sensor, it can be unstable.

[Ausman]

Sometimes encoders for this sort of thing can be replaced by laser distance measuring, depending on how clean things can be kept. I don't think you are looking for, or need, sub-mm accuracy and such sensors would be very easy to install and for your needs not that expensive.

cheers, Aus

[kratmel]

As a control option without tampering with the crane circuit, I would consider installing electromagnetic or pneumatic retractable pins in the crane sensor path to create the desired stop point.

Also possible the installation addon sensors (20pcs) that the crane is in the right position, but I think that this is not the worst option - because it will tell the user exactly where the crane stopped.

Well, if you completely simplify the task - install 5 sensors on the crane and read the absolute position of the crane encoded in a binary code (32 possible for 5 sensors) mechanically or optically with special stop position plates with slots.

However, a method with retractable pins would probably be a good solution from the point of view of not interfering with the electric diagrams of the crane. I would not use the endstop points from the crane manufacturer, and that is the main thing.

The most important in your system is the mandatory control of the absence of people in the area of automatic operation of the crane. There are appropriate safety standards for this, fences with an access control system should be installed, similar to robots.

[RickL]

Hi Deyan!   :  )

This is my first PLC project as well!

Have you considered using a retraction cabled digital absolute encoder for your project? 

I'm using one in my current project, in a similar fashion,  but vertical application.

I'd be happy to help in your hardware and software development to get your project on-line ....... hopefully you can help me with my project too!  

Absolute Digital Encoders

 

Fields of application:

• Positioning of rack operation equipment
• Positioning grippers and trolleys with cranes
• Automated guided systems
• Elevators
• Lifting platforms