Pump Sequencing RSLogix 5000 and FTView ME

I am working on a PLC program to allow an operator to select the order (of 6 pumps) that they would like them to start in. For example I have an overview screen with 6 pump graphics, and I would like the operator to be able to select the pumps (by pressing a button near the pump graphic) in the order that they want them to start up in (any order they like, 5,4,3,6,1,2 or any other order). How can I monitor and keep track of the order that they select the pumps? I have an array tag with 6 elements in RSLogix that can hold these values but can't figure out how to send the pump number to the correct element in the array based on the order the buttons are pressed.

Please help.

Thanks.

This subject has been discussed over and over in this forum.

Try doing a search and see what it comes up with.

Mark

I have done a search, but I can only find where they are trying to cycle the pumps on a not so random sequence: 1,2,3,4,5,6 to 2,3,4,5,6,1 to 3,4,5,6,1,2.

This does not help me. I would like to select the pumps in any order from the touch screen and update a sequence array to start the pumps in that order.

Thanks.

Here is one thread that I think may help.
http://www.plctalk.net/qanda/showthread.php?t=67719&highlight=pump+rotation

Have you tried some indirect addressing with the array based on the pumps chosen on the HMI screen?

Please explain what you mean by indirect addressing?

Wfortuny,

Look at this thread, then go to Post #31 for an exact answer to your homework problem with a 6-motor sequencer running on RSLOGIX5000. (Well, these were fans, but pumps, fans, widgets, who cares?)

http://www.plctalk.net/qanda/showthread.php?t=67554&highlight=pump+sequence&page=4

The first thing that came to mind when I read your post:

How does the operator fix it when they choose the wrong order? (If this could be an issue, I suggest using a data entry field which lets them type in a number for the order).

Once you know how to deal with that (or not deal with it), then there must be some way shape or fashion to start from the beginning with no pumps selected.

When that event happens, FLL Source 0, PumpOrder[0], Length 6, CLR N. I used PumpOrder[N] as an example tagname and N as an example for indirect addressing.

When any of the six buttons are pressed, move the value representing that button into PumpOrder[N] and then increment N.

So, when they press pump 4, stuff a value of 4 into PumpOrder[0] (because N=0), and increment N.

Then they press button for pump 3 so you stuff a 3 into PumpOrder[1] because N=1, then increment it again.

When N=6 they have all been assigned. There is nothing to keep a person from selecting the same pump twice though. If that is necessary, I would simply latch six bits (one for each pump) as they are chosen, and use those bits to inhibit their subsequent selection. When the "reset and clear everything out" event occurs, unlatch the six bits.

OkiePC said:

The first thing that came to mind when I read your post:

How does the operator fix it when they choose the wrong order? (If this could be an issue, I suggest using a data entry field which lets them type in a number for the order).

Once you know how to deal with that (or not deal with it), then there must be some way shape or fashion to start from the beginning with no pumps selected.

Click to expand...

I use two sets of registers, preset and working, to program a random sequence selection like this. The operator enters the the pump numbers in the desired sequence into the preset registers. A simple test must be passed to verify that the presets are valid before they can be copied to the working registers: Any given set of unique numbers will have a unique combination of sum and product. When the preset pass the test, the Save button lights up and can be touched/clicked to update the working registers. For pumps 1 through 6, the sum is 21 and the product is 720.