Reading direct address variables from JSON-RPC

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Hey,   I am trying to read a set of variables that are declared with direct addressing in the configuration, e.g.:   VAR_GLOBAL     {S7.Extern=ReadOnly}     Variable1 AT %I42.0 : BOOL;     {S7.Extern=ReadWrite}     Variable2 AT %MB100 : WORD; END_VAR   They show up fine when browsing the TGlobalVariablesDB via the Json RPC, BUT ONLY if I omit the addressing. When I add the addressing it is as if they were declared {S7.Extern=Hidden}.   I can't find any mention of such a limitation in the documentation. Is this a bug or a feature?
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1 answers
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Hi Simon ...

 

from a conceptual perspective, and without diving into specific system implementation details:

 

Globally declared variables in SIMATIC AX (as of this writing this) are stored within the "TGlobalVariablesDB" Datablock, leveraging an optimized data layout.

In contrast, globally declared Memory, Timer/Counter (T/C), and I/Q variables in SIMATIC AX are defined within their respective memory layers. Consequently, they are NOT stored in the generalized "TGlobalVariablesDB".

However : It is anticipated that these variables will be in the same locations on the PLC after download, as TIA Portal loads them into the M, T/C, and I/Q areas respectively.

 

Greetings 

 

Keep going & happy coding ...

🐱‍💻 BEEP, BOOP, BEEP, BEEP, BOOP 🐱‍🏍

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