https://forge.codesys.com/forge/talk/CODESYS-V2/thread/157026f4e3/2020-02-27T22:44:10.581000ZRecent posts to Endless FOR Loop with CoDeSys 2.3.9.x2020-02-27T22:44:10.581000Z2020-02-27T22:44:10.581000Zshooterhttps://forge.codesys.com/u/shooter/https://forge.codesys.comd42dcb074a50c450888af6929f68772d1b89827a

<div class="markdown_content"><p>no you are in error, as it is overflowing, </p> <p>when the test is on zero before adding it would not start at all</p> <p>when the test is on 255 then it would not run the last one. And yes correct you get endless loop.</p> <p>this is same for word and dword and for int,dint all same problem.</p> <p>very old problem even in machinelanguage was this a problem.</p></div>

2020-02-27T22:44:08.924000Z2020-02-27T22:44:08.924000Zyanapahttps://forge.codesys.com/u/yanapa/https://forge.codesys.com7e458a66f04747736617d3dc3418620bec377daa

<div class="markdown_content"><div class="codehilite"><pre><span></span><span class="nv">PROGRAM</span> <span class="nv">PLC_PRG</span> <span class="nv">VAR</span>    <span class="nv">i</span> : <span class="nv">BYTE</span><span class="c1">;</span>    <span class="nv">Test</span> : <span class="nv">WORD</span><span class="c1">;</span> <span class="nv">END_VAR</span> <span class="k">FOR</span> <span class="nv">i</span>:<span class="o">=</span> <span class="mi">0</span> <span class="nv">TO</span> <span class="mi">255</span> <span class="k">DO</span>    <span class="nv">Test</span> :<span class="o">=</span> <span class="nv">Test</span> <span class="o">+</span> <span class="mi">1</span><span class="c1">;</span> <span class="nv">END_FOR</span><span class="c1">;</span> <span class="nv">Test</span> :<span class="o">=</span> <span class="mi">0</span><span class="c1">;</span> </pre></div> <p>There is a mistake in the IEC61131 compiler, the loop exit condition must be verified before increasing the i value and when exiting just increase once more like other compilers.</p></div>