Statement List (STL) - DCE FEL ČVUT v Praze

12.3 FR Enable Timer (Free)
Format
FR
Timer Instructions
Address Data type Memory area Description
TIMER T Timer number, range depends on
CPU
Description of instruction
Status word
Example
When the RLO transitions from "0" to "1", FR clears the edge-detecting flag
that is used for starting the addressed timer. A change in the RLO bit from 0 to 1 in
front of an enable instruction (FR) enables a timer.
Timer enable is not required to start a timer, nor is it required for normal timer
instruction. An enable is used only to re-trigger a running timer, that is, to restart a
timer. The restarting is possible only when the start instruction continues to be
processed with RLO = 1.
BR CC 1 CC 0 OV OS OR STA RLO /FC
writes: - - - - - 0 - - 0
STL Explanation
A I 2.0
FR T1 //Enable timer T1.
A I 2.1
L S5T#10s //Preset 10 seconds into ACCU 1.
SI T1 //Start timer T1 as a pulse timer.
A I 2.2
R T1 //Reset timer T1.
A T1 //Check signal state of timer T1.
= Q 4.0
L T1 //Load current time value of timer T1 as a binary number.
T MW10
Statement List (STL) for S7-300 and S7-400 Programming
A5E00706960-01 12-5