1 Basic Principles of PLC Ladder Diagram
DVP-PLC Application Manual
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7. STL instruction: Used for designing the syntax of the sequential function chart (SFC).
STL instruction allows the program designer a clearer and readable picture of the sequence of the program as
when they draw a sequence chart. From the figure below, we can see clearly the sequence to be planned. When the
step S moves to the next step, the original S will be “Off". Such a sequence can then be converted into a PLC ladder
diagram and called “step ladder diagram”.
M1002
S0
SET
S0
S0
SET
S21
SET
S22
S
S21
S
RET
S22
S
M1002
8. RET instruction: Placed after the completed step ladder diagram.
RET also has be placed after STL instruction. See the example below.
RET
S20
S
RET
S20
S
X1
X1
See step ladder instructions [STL], [RET] in Ch. 4 for the structure of the ladder diagram.
Summary of Contents for DVP-PLC
Page 1: ...PLC PLC...
Page 28: ...1 Basic Principles of PLC Ladder Diagram DVP PLC Application Manual 1 24 MEMO...
Page 192: ...4 Step Ladder Instructions DVP PLC Application Manual 4 22 MEMO...
Page 472: ...8 Application Instructions API 100 149 DVP PLC Application Manual 8 70 MEMO...
Page 574: ...9 Application Instructions API 150 199 DVP PLC Application Manual 9 102 MEMO...