STL pointers problem

Aret

Amir, i've done several times what you're trying to implement - in my case it works.

L P#M0.0 // ACCU will contain 16#83000000 - i.e. memory area + address

T MD4

L B[MD4] // it would be implemented as L MB0

is fine. Although i would replace MD4 for AR1 (T MD4 is replaced to LAR1 in that case). This will ensure nothing will overwrite your address.

Aret

Dear Amir, now i can see your problem Area-crossing indirect addressing doesn't work with pointer placed in memory cells (to be honest i was sure it would). It works only with AR1/2 registers. So code is

L P#M 23.0
LAR1

L DW#16#12345678
T MD 20 // MB20= 12, MB21=34, MB22=56, MB23=78

L B [AR1,P#0.0]
T MB 50 // MB50 now contains 78

Thank you pointing out this problem!

Could you tell me where to find the "Pointers and Indirect adressing" document? or could you send me a copy? 

AmirAlwaled

I was reading pdf :" Pointers and Indirect addressing in S7 PLCs, volume 1- Memory Indirect addressing " ,

and when I tried this code :
[code]L MB [MD4][/code]
it works but when I tried this code :
[code]L B [MD4][/code]
it didn't !
why ?

controlsgirl317

Could you tell me where to find the "Pointers and Indirect adressing" document? or could you send me a copy? 

AmirAlwaled

I was reading pdf :" Pointers and Indirect addressing in S7 PLCs, volume 1- Memory Indirect addressing " ,

and when I tried this code :
[code]L MB [MD4][/code]
it works but when I tried this code :
[code]L B [MD4][/code]
it didn't !
why ?

 

 Hello controlsgirl317,

Go to the second page of the thread below and look the 2 pdf of Sydney maybe her they:

indirect addressing with pointers - Siemens Industry Online Support ...