SCL 语法速查：块、变量、控制流与常用指令

1FUNCTION_BLOCK "FB_Lamp"
2{ S7_Optimized_Access := 'TRUE' }
3VERSION : 0.1
4   VAR_INPUT
5      Switch : Bool;
6   END_VAR
7   VAR_OUTPUT
8      Lamp : Bool;
9   END_VAR
10BEGIN
11   #Lamp := #Switch;
12END_FUNCTION_BLOCK

1FUNCTION_BLOCK "FB_Counter"
2VERSION : 0.1
3   VAR_INPUT
4      CountUp : Bool;
5   END_VAR
6   VAR_OUTPUT
7      Count : Int;
8   END_VAR
9   VAR
10      Prev : Bool;
11   END_VAR
12   VAR_TEMP
13      Rising : Bool;
14   END_VAR
15   VAR CONSTANT
16      STEP : Int := 1;
17   END_VAR
18BEGIN
19   #Rising := #CountUp AND NOT #Prev;
20   #Prev := #CountUp;
21   IF #Rising THEN
22      #Count := #Count + #STEP;
23   END_IF;
24END_FUNCTION_BLOCK

1#Ok := (#Temp > #Min) AND (#Temp < #Max) AND NOT #Fault;

1#Count := #Count + 1;
2#Total += #Value;   // 等价于 #Total := #Total + #Value
3#Total -= #Value;
4#Total *= 2;
5#Total /= 2;

1IF #Start THEN
2   #Run := TRUE;
3ELSIF #Fault THEN
4   #Run := FALSE;
5ELSE
6   #Run := #Run;
7END_IF;

1CASE #State OF
2   0:
3      IF #Start THEN
4         #State := 1;
5      END_IF;
6   1:
7      IF #Done THEN
8         #State := 2;
9      END_IF;
10   ELSE
11      #State := 0;
12END_CASE;

1FOR #i := 1 TO 8 DO
2   #Sum := #Sum + #Array[#i];
3END_FOR;
4 
5FOR #i := 8 TO 2 BY -1 DO
6   #Array[#i] := #Array[#i - 1];
7END_FOR;
8 
9WHILE #i < 10 DO
10   #i := #i + 1;
11END_WHILE;
12 
13REPEAT
14   #i := #i + 1;
15UNTIL #i >= 10
16END_REPEAT;

1VAR
2   Timer : TON_TIME;
3END_VAR
4 
5#Timer(IN := #Start, PT := T#3S);
6#Q := #Timer.Q;
7#ET := #Timer.ET;

1VAR
2   Counter : CTU_DINT;
3END_VAR
4 
5#Counter(CU := #Pulse, R := #Reset, PV := 10);
6#Done := #Counter.Q;
7#Count := #Counter.CV;

1VAR
2   Prev : Bool;
3END_VAR
4 
5#Rising := #Signal AND NOT #Prev;
6#Falling := NOT #Signal AND #Prev;
7#Prev := #Signal;

1VAR
2   Trig : R_TRIG;
3END_VAR
4 
5#Trig(CLK := #Signal);
6#Rising := #Trig.Q;

1VAR
2   Slots : Array[1..8] of Struct
3      Loaded : Bool;
4      Age : Time;
5   END_STRUCT;
6   Names : Array[0..3] of String[20];
7END_VAR
8 
9#Slots[1].Loaded := TRUE;
10#Slots[1].Age := T#0MS;
11#Names[0] := 'Part-A';

1#Slots[#i] := #Slots[#i - 1];

1VAR
2   Text : String[60];
3   Len : Int;
4END_VAR
5 
6#Text := 'Valve not opening';
7#Len := LEN(#Text);
8#Text := CONCAT(IN1 := 'Valve: ', IN2 := #Text);

1#RealValue := INT_TO_REAL(#IntValue);
2#IntValue := REAL_TO_INT(#RealValue);
3#WordValue := INT_TO_WORD(#IntValue);

1#Total := T_ADD(IN1 := #Total, IN2 := #CycleTime);
2#Diff := T_SUB(IN1 := #EndTime, IN2 := #StartTime);
3#Ms := TIME_TO_DINT(#Total);

1// 调用 FB，使用背景 DB
2"DB_Motor"(Start := #Start, Stop := #Stop, Motor => #Motor);
3 
4// 调用 FC（无背景 DB）
5#Result := "FC_Add"(A := 1, B := 2);

1// 单行注释
2(* 块注释，可嵌套 *)
3REGION 状态机
4   // ...
5END_REGION