Advice on sensor selection for rail-cart application

kalabdel

Member
Join Date
Feb 2015
Location
Ontario
Posts
1,108
Hello guys,


Imagine wagons,carts,tables or anything similar that are about 4 feet wide by 8' long riding on a rail system. Each lane of rails can accommodate 40-50 of those. They are moved by a motor and an arm thingie that moves from one end only. So a cart enters the line and is pushed tight against the one before it and the whole line gets pushed down the rails until the lane is full and the cart at the front is moved out allowing for more carts to enter the beginning of the line. So the arm moves only about 4 feet or so.

The problem is that when a cart gets derailed for whatever reason the motor just keeps going and damages one or more carts and of course interrupts production. There currently is a trip wire that is installed under the carts with the whole length of the rail so if a cart tips/derails it touches that wire and stops the drive. That system is not very effective as sometimes it doesn't work and sometimes it parts of the carts (wheels for example) catch the wire and trips the system.

There are hundreds of those cars in any lanes traveling around and around from one lane to another carrying product. Installing a sensor of whatever type on every cart is too expensive.
I considered installing an encoder on the motor or gearbox and will test that in the near future. I was also thinking about a long range laser/photo sensor but it would have to be very precise to shoot through right under the carts and detect about an inch of obstruction.


Any suggestion would be greatly appreciated.


Cheer

Kal
 
What about a pressure plate affair? Place lengths of steel plate mounted on springs beside the rails. Under the plates are one or more limit switches actuated when the wheel of the derailed cart presses on the plate. The switches are wired in series like an E-stop circuit such that any switch activation shuts down the line. Use switch with a second set of contacts and you could easily determine where the derailment is by feeding switch location to an HMI or, even a locally positioned flasher.


Just sayin'.

derail detector.png
 
I believe we have 52 lanes each with a pair of rails, each 250 feet long and I have to know if a cart is derailed anywhere along the rail.
 
I believe the each lane would be about 400Ft long with 52 lanes that's a lot of material
Also pushing 50 carts from one end is a disaster, trains don't push they pull.
I think I would consider a laser down each side of the rails if a wheel drops off the rail brakes the beam sets the alarm if you need to know exactly witch cart derailed then you would have to set up a grid of sensor's it could get very completed quickly.
it may be better to power each cart separately battery pack or power rail that way you could keep them from crashing into each other
 

Similar Topics

Hey guys, We have a metal container at work, we fill with saw dust (20fts x 15fts x 10fts) with the top open but we normally put a container...
Replies
4
Views
1,531
Hey guys, I'm looking for some advice for my project. We are trying to datalog the temperature of a wooden log, it can vary from 35C to 70C. and...
Replies
3
Views
1,659
Any photosensor experts out there? My first photo sensor project and I need some advice. The application is to detect ice falling in an ice pen...
Replies
3
Views
1,548
I need a kind of a light curtain, measuring the width of passing object (that is, the number of interrupted beams). Output signal format is not...
Replies
9
Views
3,545
Hi everyone id like to start by saying im not a PLC programmer so my technical terminology is limited. i would like advice on what software is...
Replies
4
Views
269
Back
Top Bottom