Timer Instructions
Statement List (STL) for S7-300 and S7-400 Programming
12-16
A5E00706960-01
12.9 SD On-Delay Timer
Format
SD <timer>
Address Data type Memory area Description
<timer> TIMER T Timer number, range depends on
CPU
Description of instruction
SD <timer> starts the addressed timer when the RLO transitions from "0" to "1". The
programmed time interval elapses as long as RLO = 1. The time is stopped if RLO
transitions to "0" before the programmed time interval has expired. This timer start
instruction expects the time value and the time base to be stored as a BCD number
in ACCU 1-L.
See also Location of a Timer in Memory and Components of a Timer.
Status word
BIE A1 A0 OV OS OR STA VKE /ER
writes: - - - - - 0 - - 0
Example
STL Explanation
A I 2.0
FR T1 //Enable timer T1.
A I 2.1
L S5T#10s //Preset 10 seconds into ACCU 1.
SD T1
//Start timer T1 as an on-delay 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 timer value of timer T1 as binary.
T MW10
LC T1 //Load current timer value of timer T1 as BCD.
T MW12
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