adding arrays

asterof · Nov 16, 2011

so I have 32 arrays of real
each array has 4 words
array1[0] - [3]
array2[0] - [3]
and so on

I need to add each element to the next array same element
example x = array1[0] + array2[0] + array3[0]
and so on

using a cpt would be ugly and hard to read

is there a way maybe to use an FAL to do this

jkerekes · Nov 16, 2011

A FAL will do what you want.

Lancie1 · Nov 16, 2011

Set up a For-Next loop;

For I = 0 to 3
x(I) = array1 + array2 + array3
Next I

asterof · Nov 16, 2011

Controllogix

Lancie1 said:
Set up a For-Next loop;

For I = 0 to 3
x(I) = array1 + array2 + array3
Next I

Could do that if I was using Step7 or Modicon
However Controllogix does not have that
capability

asterof · Nov 16, 2011

tried that also, but you still need a ton of expressions
have not seen a way to index the arrays, I can use .pos to
index the array its self like array1[fal.pos] but not
array[FAL.POS][0]+ Holding_Array[0]

Lancie1 · Nov 16, 2011

I don't know - I have set up For Next loops in RSLogix, so I would think it could be done with Controllogix. The PLC loops every scan, so all you have to do is implement the index counter.

If you can't index an array, then in my book it is not a true array. The main reason to use the array structure is to allow easy automated access with indexing. Without that, all you have is a collection of data.

TConnolly · Nov 16, 2011

The FAL instruction is perfect for this.

It would get even simpler if you made a single 32x4 array.

asterof said:
Could do that if I was using Step7 or Modicon
However Controllogix does not have that capability

You are mistaken. The CLX has a FOR/NEXT instruction in both ladder and ST languages, or you can roll your own using JMP/LBL pairs.

asterof · Nov 16, 2011

Alaric said:
The FAL instruction is perfect for this.

It would get even simpler if you made a single 32x4 array.

You are mistaken. The CLX has a FOR/NEXT instruction in both ladder and ST languages, or you can roll your own using JMP/LBL pairs.

I will look for it
Never had to use one before
what tap is that under as I do not see it

PLCMentor · Nov 16, 2011

For some reason it doesnt look like there is a FOR instruction listed in the structured text tabs. I couldnt find it; however it does show up if you look for it in the instruction help. There are two of them. One is a ladder style instruction that allows you to cycle through a routine a number of times. The other is the FOR / DO pair that are for structured text and works pretty much like a FOR / NEXT pair.

asterof · Nov 16, 2011

screen shot

could you drop a screen shot here
would appreciate it
running on 2008 server standard and for some reason the
ver 16 help files are no longer supported

Lancie1 · Nov 16, 2011

Most of you all know that For-Next loops can be nested, so that multi-dimensional arrays can be manipulated, for example:

 

For J = 0 to 30 Step 3

For I = 0 to 3 Step 1

x(I) = array[J, I] + array[J+1,I] + array[J+2,I]

Next I

Next J

jkerekes · Nov 16, 2011

How about this:

asterof · Nov 16, 2011

clarity

yea but maybe I was not clear

I have 32 arrays of different names
each array has four elements
I need to add element 0 of each array to each other
tot_array1[0] = array1[0] + array2[0] + array3[0] + .... + array32[0]
tot_array1[1] = array1[1] + array2[1] + array3[1] + ....
+ array32[1]

I can not make a 32 x 4 element array
I can do this using an FAL with and external indexing dint

and I need to do this in an AOI because of the number
of these required
so I am passing the arrays by reference

adding arrays

asterof

Member

jkerekes

Member

Lancie1

Lifetime Supporting Member

asterof

Member

asterof

Member

Lancie1

Lifetime Supporting Member

TConnolly

Lifetime Supporting Member

asterof

Member

PLCMentor

Member

asterof

Member

Lancie1

Lifetime Supporting Member

jkerekes

Member

asterof

Member

Similar Topics