Indirect addressing of an array

lauwerstim · Oct 31, 2014

I'm creating an FB with a variable input and I would like to copy all of the bits to an array (declared as temp)

I've declared the array in TEMP: Array_TEMP;Array [1..100] of bool
I've declared the input pointer: First_SI; pointer

I read in the pointer and can get its data, but copying to the array doesn't work. This is my code so far:

Code:

 L     P##First_SI
      LAR1  
      L     W [AR1,P#0.0]
      T     #iDB
      OPN   DB [#iDB]
      L     D [AR1,P#2.0]
      L     P#0.0
      +I    
      T     #TempPoint
      A     DBX [#TempPoint]
      =     #Array_TEMP[ [I][COLOR="Red"]what goes here?[/COLOR][/I]]

When I read the first BOOL (A DBX [#TempPoint]) the outcome is correct but I can't pass it on to the array in indirect fashion. (the goal is to create a loop to copy all 100tags)

L D[AR2P#0.0] · Oct 31, 2014

You cannot specify a variable array index in s7-300, you must use another pointer and indirectly address the array elements that way.

lauwerstim · Oct 31, 2014

L D[AR2 said:
You cannot specify a variable array index in s7-300, you must use another pointer and indirectly address the array elements that way.

Too bad. Have to find another solution then.
Thanks.

lauwerstim · Oct 31, 2014

Another question then:

I have an FB that needs a STRUCT as IN/OUT, how can "indirectly" adress this IN/OUT.

The FB needs to be called 20 times and it would be handy to have this STRUCT as a variable.

L D[AR2P#0.0] · Oct 31, 2014

Why do you want to access the struct indirectly - one of the benifits of a struct is the ability to access the elements by name?

lauwerstim · Oct 31, 2014

I'll explain in short.

I have 24 elements (automated circuit breakers), each element has 64 single informations (every information needs to be attached to a FB so timestamp and quality can be added and sent to a dispatching), it has 32 double informations (attached to a different type of FB), 3 commands (different FB) and 2 measurements (yet another FB)

So now I'm trying to make 1 multi-instance FB per element so that the program would be easily scaleble (next project will have 48 elements)

cjd1965 · Oct 31, 2014

why not make a udt of type element? ID as INT, PassFail as BOOL, TIMESTAMP AS DATE_TIME

and then access the udt inside your FB

Either that or have a global DB of elements so you can easily add more if required

L D[AR2P#0.0] · Oct 31, 2014

lauwerstim said:
I'm creating an FB with a variable input and I would like to copy all of the bits to an array (declared as temp)

Here's an example implementation. I've used SFC20 to perform the copying of the data from the input to the arrray in the temp area.

I've added some test code that copies the temp array to a db as it is not easy to monitor data in the temp area for testing.

lauwerstim · Nov 3, 2014

The attached file doesn't seem to be complete, I can't open it in Step7 v5.5

edit: Sorry, my bad. Opens perfectly.

Will try it, looks promising. Thanks.

Indirect addressing of an array

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