创建定时循环结构化文本

您似乎对 CODESYS 如何运行代码有误解。与代码从上到下执行一次的 C/C++ 等语言不同，在 codesys 中，只要控制器有电，代码每秒就会执行多次（在我工作的 PLC 上，它每 20 毫秒执行一次，或者换句话说，每秒 50 次）。

因此，您不能拥有停止/延迟执行的功能。计时器在 CODESYS 中的实际作用是记住您第一次调用它们的时间，然后在每次调用时它们只检查经过了多少时间（它们不会停止！）。一旦设定的时间过去，他们会在他们的输出上提出一个标志，这样你就可以执行一些任务。

因此，让我们分解运行代码时发生的情况：

// first run:
FOR vCount := 0 TO 800 DO
    // on first itewration (vCount = 0) this will remember the current time,
    // however it won't stop here and it will continue to the next line.
    // on next iterations (vCount >= 1) the timer will check the elapsed time,
    // which will be 0, so it will do nothing and continue to the next line.
    fbBlink(ENABLE := TRUE, TIMELOW := T#1s, TIMEHIGH := T#1s, OUT => bSignal);
    // the timer just started so bSignal is FALSE
    IF bSignal THEN
        vVsample[vCount] := INT_TO_REAL(WORD_TO_INT(vVin));
    END_IF
END_FOR

// second run:
FOR vCount := 0 TO 800 DO
    // the timer will compare current time to the recorded first time.
    // the elapsed time is below the target, so skip to the next line.
    // this will be repeated 800 times for no good reason...
    fbBlink(ENABLE := TRUE, TIMELOW := T#1s, TIMEHIGH := T#1s, OUT => bSignal);
    // the timer hasn't reached target time so bSignal is FALSE
    IF bSignal THEN
        vVsample[vCount] := INT_TO_REAL(WORD_TO_INT(vVin));
    END_IF
END_FOR
// the above will reapeat for another 48 cycles

// 50th run:
FOR vCount := 0 TO 800 DO
    // the timer will compare current time to the recorded first time.
    // the elapsed time has reached the target 1 second (TIMELOW := T#1s),
    // so it will raise the OUT flag to TRUE.
    // the comparison will happen on every 800 iterations, and every time
    // it will be set to TRUE.
    fbBlink(ENABLE := TRUE, TIMELOW := T#1s, TIMEHIGH := T#1s, OUT => bSignal);
    // since bSignal is TRUE on every iteration, ener the if for every element.
    IF bSignal THEN
        vVsample[vCount] := INT_TO_REAL(WORD_TO_INT(vVin));
    END_IF
END_FOR

如果您想要每秒向数组添加一个值，那么您可以这样做（请注意，这不会停止/停止/延迟执行，并且此后的代码仍将在每次运行时执行.如果这是不受欢迎的，你必须单独处理）：

timer(IN := vCount <> 801, PT := T#1S); // timer is TON
IF (timer.Q) THEN
    timer(IN := FALSE); // reset the timer so it starts counting again nextr run
    vVsample[vCount] := INT_TO_REAL(WORD_TO_INT(vVin));
    vCount := vCount + 1; // increment the counter
END_IF