S5-100U STEP 5 Operations
8.2.2 Enable Operation, for CPU 103 and Higher
You can use the enable operation (FR) to execute the following operations even without an edge
change.
• Start a timer
• Set a counter
• Count up and down
Table 8-11 presents the enable operation. An example follows the table.
Table 8-11. Enable Operation
Operation Meaning
Parameter
0 to 127
0 to 127
Operand
FR Enable a Timer/Counter
Timers and counters are enabled on the leading edge of the RLO.
This operation restarts a timer, sets a counter, or causes a counter
to count up or down when the RLO “1” is pending at the “Start”
operation.
ID
T
C
STL ExplanationExample
Input I 0.0 starts a timer T 2 as an
extended pulse (pulse width 50 s).
This timer sets output Q 1.0 for the
duration of the pulse.
.
.
.
.
If output Q 1.1 is reset repeatedly, the
timer should also be restarted
repeatedly.
A I 0.0
L KT 500.1
SE T 2
AT2
= Q 1.0
.
.
.
.
A Q 1.1
FR T 2
BE
Start a timer T 2 as an extended
pulse.
Output Q 1.0 is set for 50 s.
If output Q 1.1 is set (positive
edge change of the RLO) during
the time in which input I 0.0 is
set, timer T 2 is restarted. Output
Q 1.0 therefore remains set at the
restarted time or is reset.
If input I 0.0 is not set during the
edge change of output Q 1.1, the
timer is not restarted.
EWA 4NEB 812 6120-02
8-41
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