Question about ANYPOINTER and POINTER in Step7

bara_hence · Mar 6, 2009

Have a little question how to do this:

I want to do a ANY pointer wich gets a DBnr (INT) and number of bytes to send and number of bytes to send (INT) The question i have is when makiing the last part of the ANYPOINTER for the SEND area i want to use the recieve areas lenght to set the start adress is this possible to do? This is what I have come up with:

L #RecvLen
SLD 3
T D [AR1,P#6.0]

Will that work to point out the startadress for example dbx50.0 (if RecvLen = 50)??

The other code follows:

Code:

L     #SendDB_Nr
T     #Temp_DB_Nr


//************************************
// Build Anypointer Send
//************************************
      L     P##P_Send
      LAR1  

// System-Code

      L     B#16#10
      T     B [AR1,P#0.0]

// Datatype Byte

      L     B#16#2
      T     B [AR1,P#1.0]

// Number of Bytes to Exchange

      L     #SendLen
      T     W [AR1,P#2.0]

// DB Nr.

      L     #Temp_DB_Nr
      T     W [AR1,P#4.0]

// Start-Adress i DB  OBS möjligt att göra?
//L     #RecvLen
//SLD   3
//T     D [AR1,P#6.0]

      L     P#DBX 50.0
      T     D [AR1,P#6.0]

//*********************************************
// Build Anypointer Recv
//*********************************************

      L     P##P_Recv
      LAR1  

// System-Code

      L     B#16#10
      T     B [AR1,P#0.0]

// Datatype Byte

      L     B#16#2
      T     B [AR1,P#1.0]

// Number of Bytes to Exchange

      L     #RecvLen
      T     W [AR1,P#2.0]

// DB Nr.

      L     #Temp_DB_Nr
      T     W [AR1,P#4.0]

//Start-Adress i DBt


      L     P#DBX 0.0
      T     D [AR1,P#6.0]

L D[AR2P#0.0] · Mar 6, 2009

Code:

L #RecvLen
SLD 3
T D [AR1,P#6.0]

is the equivilant of

Code:

L P#50.0
T D[AR1,P#6.0]

for your example. You need to declare an area for the pointer
so if you want to use DBX then use the following:

Code:

L #RecvLen
SLD 3
L P#DBX0.0
+D
T D [AR1,P#6.0]

bara_hence · Mar 6, 2009

Aah Ok thanks a little question this code will be used in a FB pointing to a DB outside it but when using pointers then i dont have to Open the DB i point to or do I??

Siemens is great but sometimes digging thrue all the things you can do with it is hard..

Do you have any manuals on the Pointer,ANY pointer and such that you or anyone else can recommend reeding??

L D[AR2P#0.0] · Mar 6, 2009

If you are generating pointers for copying via SFC20 then you will not be accessing any data in the DB so there will be no need to open it.

The information on pointers/anypointers in Berger's book is an excellent reference.

bara_hence · Mar 6, 2009

What do you mean by accessing data?

I mean if I use a pointer as the location to copy data to arent I accessing that area then or do you mean that Im not acessing the area?

This will be used with TSEND, TRECV SendPointer that points to area that will be sent and recv pointer that points to area to write data..

Ive looked in Bergers book for a year ago or something like that but i didnt understand much then but maybe i have come to the point where his books starts making sense.. In my point of view he starts at a little high level for the novice in step7..

L D[AR2P#0.0] · Mar 6, 2009

bara_hence said:
What do you mean by accessing data?

..if you use load or transfer operations on data in the DB (in which case you had better have opened the correct DB otherwise you will access data in the currently opened DB)

bara_hence · Mar 6, 2009

Ok thanks for the help really appreciated

Question about ANYPOINTER and POINTER in Step7

bara_hence

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