Simple Sortation Application

[Techhead Tom]

Hi Guys,
I have a small sortation conveyor that I am going to write a program for and would like some suggestions for the right approach to take. I have done a sortation before using a FIFO and counters to track the product from the scanner to the proper lane where it needs to be diverted. Each diverter had a PE to aid in exact placement and I used these PE inputs to keep the counters equal. There was a counter for each diverter as well a one for the PE at the scanner. When product A was in front of the PE at the scanner and was identified as Product A, whatever the value of the counter was at that given time would be moved into the FIFO for diverter 1 and when the counter for diverter A was equal to that value and the PE at Diverter A indicates that the product is in position it would divert the product. I also indexed each counter that was down conveyor 1 count everytime that an up conveyor product was diverted. The reason for using FIFO is that many products would be in the sortation area at any given time. This works very good but it seems to me that there would be a simpler way to approach this.

The new project conveyor will be running at 100 feet per minute with different size boxes. There will be three different product types with 2 divert lanes and the 3rd product type continuing straight. The conveyor will be a belt conveyor unlike the above project whick was live roller. Cost is a big concern so I want to keep programming and hardware cost to a min. I will be using a micrologix 1000 or 1200. Again I am just looking to see what kind of concepts anyone else has in mind.

 

[elevmike]

You may want to take a look at this thread:

http://www.plctalk.net/qanda/showthread.php?t=9612&highlight=fifo+sort

 

[Techhead Tom]

You may want to take a look at this thread:

http://www.plctalk.net/qanda/showthread.php?t=9612&highlight=fifo+sort

Thanks for the link. There are some very good ideas there. If anyone else has something to add I would love to hear your ideas.

 

[Terry Woods]

"The new project conveyor will be running at 100 feet per minute with different size boxes. There will be three different product types with 2 divert lanes and the 3rd product type continuing straight. The conveyor will be a belt conveyor unlike the above project whick was live roller."

                           _____________________

                          /  1       1 1     1

                         /   ____________________

  SCAN               #1 / 1 /           EYE

   _|__________________/   /_____________|_________________

      2,1,1,0,2,0,1         2,0,0,2,2,2,0      0   0   0 0

   ________________________________________    ____________

          FIFO #1     |        FIFO #2     \   \      

                     EYE                 #2 \ 2 \__________

                                             \     2    2

                                              \___________

In general...

A part arrives at the scanner... the type is determined. The type-number is loaded into FIFO #1.

When Eye sees part at Diverter #1, the program looks at the current value of the "out-word" in FIFO #1.

If the value is "1" then the box is diverted and the value in the "out-word" is discarded.

If the value is "0" or "2" then the box passes and the "out-word" is loaded into FIFO #2.

When Eye sees part at Diverter #2, the program looks at the current value of the "out-word" in FIFO #2.

If the value is "2" then the box is diverted. If the value is "0" then the box passes.
In either case, the "out-word" is discarded.

There might very well be other issues such as requiring a gap between boxes.