6.1.3.3 Jump Instructions
Jump command
- The graphical elements used for program control transfer are shown in the following table:
| Serial number | Description | Example |
|---|---|---|
| 1 | Unconditional jump | +---》LABEL1 |
| 2 | Conditional jump | +---"Contact"---》LABEL1 LABEL1: Example // Label +---"Contact"---"Coil" |
| 3 | Conditional return (exit this program unit) | +----"Contact"---"RETURN" |
| 4 | Unconditional return (exit this program unit) | +-----《RETURN》 |
Label
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Function description: Can only be placed at the beginning of each program segment in the ladder diagram and used in conjunction with jump labels
-
Example:
- Label, also called jump label, is an optional indicator in ladder diagram and its address can be determined when defining a jump
- The jump label name must end with ":"
Jump label
-
Function description: Conditionally or unconditionally jump to the specified label
-
Example: If the signal state of the operand "TagIn_1" is "1", the "Jump if RLO = "1"" instruction is executed. The sequence of program execution is interrupted and continues in "Block 3" identified by the jump label CAS1. If the signal state of the "TagIn_3" input is "1", the "TagOut_3" output is set
Return
-
Function description: Conditionally or unconditionally exit this program unit module and return to the calling body
-
Example:
If the signal state of the operand "TagIn" is "1", the instruction is executed. Program execution ends in the called block and continues in the calling block. And resets the signal status of the calling program block enable output ENO to "0"
