https://forge.codesys.com/forge/talk/Engineering/thread/f3d13b1f88/2024-08-08T14:49:45.881000ZRecent posts to OPC-UA Server, Symbol Set: Raise an error: Object reference not set to an instance of an object.2024-08-08T14:49:45.881000Z2024-08-08T14:49:45.881000Zalimanshttps://forge.codesys.com/u/alimans/https://forge.codesys.com9276835875e20194990697ee374823a1741fbfc8

<div class="markdown_content"><p>Hi everyone,<br/> I just created a very simple library without any code and, added it to my very simple project. after adding this library, I get an error when I try to open "Symbol Set" in "OPC UA Server" in "Communication Manager". </p> <p>Here is the code of my POU in the library:</p> <div class="codehilite"><pre><span></span><code><span class="nt">FUNCTION_BLOCK</span><span class="w"> </span><span class="nt">POU</span> <span class="nt">VAR</span> <span class="w"> </span><span class="nt">eCommand</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="o">(</span><span class="nt">CMD_NONE</span><span class="o">:=</span><span class="nt">0</span><span class="o">,</span><span class="w"> </span><span class="nt">CMD_RESET</span><span class="o">:=</span><span class="nt">-1</span><span class="o">)</span><span class="w"> </span><span class="nt">INT</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nt">CMD_NONE</span><span class="o">;</span> <span class="nt">END_VAR</span> </code></pre></div> <p>Attached is the error that I get.<br/> I also noticed that by removing the enumeration variable above (eCommand), I can open the "Symbol Set" again. <br/> Anybody has any idea why this error is raised and how could I use enumeration variables without error in "OPC UA Symbol Set"?</p></div>