RSL5000 BSL Question

[PLC Pie Guy]

Hey All.
I am working on a small piece of logic and I hit a roadbump here. I am trying to use a BSL but perhaps something else is in order.

I want the basic functionality of the BSL but with different characteristics.

I am trying to advance the BSL only 4 bits and then re-start at the beginning again, instead it wants to advance through the whole word. Just as its intended.

Also, I want the bits in the BSL to return to a 0 once the BSL moves to the next position.
I know I can write these bits to be a zero but is there a nicer instruction to use for this functionality.

Any ideas for this?

Thanks to any interested.

 

[PLC Pie Guy]

Ok, I got this.
It does not matter that the value of the bit flows through the word as I am only examining up to the UL bit anyway.
Alos, I simply use the CLR instruction to reset the bits to 0 after I do what I need with it.

UURRRGHH Monday!

 

[cbuysse]

Also, I want the bits in the BSL to return to a 0 once the BSL moves to the next position.
I know I can write these bits to be a zero but is there a nicer instruction to use for this functionality.

I'm glad you got it to do what you wanted, but I'm somewhat confused by the above part of your question so I just had to respond. If understand correctly, what you're seeing when you use the BSL is something like the following:
step 0 - ...0000
step 1 - ...0001
step 2 - ...0011
step 3 - ...0111
step 4 - ...1111
but what you want is:
step 0 - ...0000
step 1 - ...0001
step 2 - ...0010
step 3 - ...0100
step 4 - ...1000

If this is the case, then all you need to do is to turn off the SourceBit for the BSL instruction after the first execution of the instruction. On the next execution, the 1 will shift over and a 0 will be placed in its place.

 

[PLC Pie Guy]

Right you are cbuysse.

That was one option that I thought about.
What I actually did was use OTU and direct it at the bit of the BSL I was interested in examining. Once it was examined it gets switched back to a 0. Then my source bit stays at a 1. Actually I am using an "Always_One" tag for the source bit.
Typically I have used BSL to track parts on a line as they pass stations, here I am using it as a place holder for six machines that need to call for fruit in order, one than the next, IF any of the machines are off, or filled, the BSL bit in question gets "unlatched" and we go to the next station. If its BSL bit is a 1, we fill.

I was having trouble getting my brain to fire up this morning!!! I guess I needed some more coffee!!
Thanks for the suggestion, there is always more than one way to skin a cat!