https://forge.codesys.com/forge/talk/CODESYS-V2/thread/a2a5534634/2020-02-27T18:55:37.808000ZRecent posts to PLCHandler.PlcSymbolDesc & ARRAY OF STRING2020-02-27T18:55:37.808000Z2020-02-27T18:55:37.808000Zshooterhttps://forge.codesys.com/u/shooter/https://forge.codesys.comdede37ff2e77e1fdfefacb64d1e8ec037cb8f128

<div class="markdown_content"><p>you can always ask the LEN of any string.</p></div>

2020-02-27T18:55:36.551000Z2020-02-27T18:55:36.551000Zeugeneehttps://forge.codesys.com/u/eugenee/https://forge.codesys.comea9ee45702cec7137c133a2a40fcf9f637887193

<div class="markdown_content"><p>Hello!<br/> I'm using PLCHandler library.<br/> Having simple IEC project with an array of strings</p> <div class="codehilite"><pre><span></span><span class="n">PROGRAM</span> <span class="n">PLC_PRG</span> <span class="n">VAR</span> <span class="n">_arr_string</span> <span class="p">:</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">..</span><span class="mi">10</span><span class="p">]</span> <span class="k">OF</span> <span class="n">STRING</span><span class="p">(</span><span class="mi">10</span><span class="p">)</span> <span class="p">:</span><span class="o">=</span> <span class="p">[</span><span class="s1">'aaa'</span><span class="p">,</span><span class="s1">'bbb'</span><span class="p">,</span><span class="s1">'ccc'</span><span class="p">,</span><span class="s1">'ddd'</span><span class="p">,</span><span class="s1">'eee'</span><span class="p">,</span><span class="s1">'fff'</span><span class="p">,</span><span class="s1">'ggg'</span><span class="p">,</span><span class="s1">'hhh'</span><span class="p">,</span><span class="s1">'iii'</span><span class="p">,</span><span class="s1">'jjj'</span><span class="p">];</span> <span class="n">END_VAR</span> </pre></div> <p>I got the list of variables by calling GetAllItems().<br/> PlcSymbolDesc for this variable contains</p> <div class="codehilite"><pre><span></span><span class="s1">'Application.PLC_PRG._arr_string'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">131085</span><span class="p">)</span><span class="o">-</span><span class="s1">'ARRAY [1..10] OF STRING'</span><span class="o">-</span><span class="s1">'ARRAY : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'110'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[10]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[1]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[2]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[3]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[4]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[5]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[6]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[7]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[8]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> <span class="s1">'Application.PLC_PRG._arr_string[9]'</span><span class="p">,</span> <span class="n">typeID</span><span class="p">(</span><span class="mi">13</span><span class="p">)</span><span class="o">-</span><span class="s1">'STRING'</span><span class="o">-</span><span class="s1">'SIMPLE : DATATYPE_STRING'</span><span class="p">,</span> <span class="k">size</span> <span class="s1">'11'</span><span class="p">,</span> <span class="k">access</span> <span class="s1">'b'</span><span class="p">,</span> <span class="n">RefId</span> <span class="s1">'0'</span><span class="p">,</span> <span class="k">offset</span> <span class="s1">'0'</span> </pre></div> <p>Reading the data by SyncReadVarsFromPlc() brings me the following (hex trace):<br/> - for single array element 'Application.PLC_PRG._arr_string<span>[1]</span>' - (length 11) - a a a 00 00 00 00 00 00 00 00 hex<br/> - for array 'Application.PLC_PRG._arr_string' - (length 110) - a a a 00 00 00 00 00 00 00 00 b b b 00 00 00 00 00 00 00 00 c c c 00 00 00 00 00 00 00 00 d d d 00 00 00 00 00 00 00 00 e e e 00 00 00 00 00 00 00 00 f f f 00 00 00 00 00 00 00 00 g g g 00 00 00 00 00 00 00 00 h h h 00 00 00 00 00 00 00 00 i i i 00 00 00 00 00 00 00 00 j j j 00 00 00 00 00 00 00 00 hex</p> <p>The question is - how can I parse the data block (length 110 bytes) which I received for whole array variable <em>arr_string? There is no info about length of each array element in PlcSymbolDesc for _arr_string.The length of each element can only be seen in PlcSymbolDesc for _arr_string<span><span>[XXX]</span></span> - 11 bytes. But symbol descriptions for the array and its elements are only linked by the symbol names - I think it's not the right way to get array element size by comparing the names of PlcSymbolDesc structures. The same with the symbol type name of the variable ('ARRAY <span><span>[1..10]</span></span> OF STRING') in the field PlcSymbolDesc.pszType. Is there any other _more_simple</em> way to handle this?</p> <p>BR, Eugene</p></div>