Omron NJ Series

6 Programming
6-110
NJ-series CPU Unit Software User’s Manual (W501)
The differences between ST and ladder diagrams are described below.
Differences between ST and Ladder Diagrams
Item Ladder diagram ST (including inline ST)
Input differ-
entiation
 Change to TRUE  Change to TRUE
• Method 1
R_TRIG_instance (Clk:=start, Q=>do);
* R_TRIG_instance is an instance of the
R_TRIG instruction.
 Change to FALSE  Change to FALSE
• Method 1
F_TRIG_instance (Clk:=start, Q=>do);
* F_TRIG_instance is an instance of the
F_TRIG instruction.
Instruction
differentia-
tion
 Upward Differentiation  Upward Differentiation
There is no equivalent in ST. You must create it
in logic.
Example:
• Method 1
R_TRIG_instance (Clk:=start, Q=>do);
IF (do = TRUE) THEN Inst();
END_IF;
• Method 2
IF (start = TRUE) THEN
IF (pre_start = FALSE) THEN Inst();
END_IF;
END_IF;
pre_start:=start;// Update previous value.
• Method 1
• Method 2
• Method 3
start do
----|↑|-----------
Up
start
do
R_TRIG
Clk Q
In
start
do
R_TRIG_instance
• Method 1
start do
----|↓|-----------
• Method 2
• Method 3
Down
start
do
F_TRIG
Clk Q
In
start
do
F_TRIG_instance
start
@Inst