S5 AWL Command: SE (Extended Pulse Timer)
S5 AWL instruction SE (Extended Pulse): Timer runs for full duration regardless of input state. Retriggerable — a new TRUE edge restarts the timer.
S5 AWL Command: SE (Extended Pulse Timer)
SE starts an extended pulse timer. Unlike SI, the timer output stays TRUE for the full programmed duration even if the input (VKE) goes FALSE before the timer expires. A new rising edge on the input restarts the timer (retriggerable).
Syntax
L KT xxx.y
SE T n
S7 Equivalent
| S5 AWL | S7 Function | IEC 61131-3 |
|---|---|---|
| SE | S_PEXT | TP (closest match, but TP is NOT retriggerable) |
Critical difference: SE is retriggerable (new edge restarts). IEC TP is not. For exact SE behavior in S7, use S_PEXT.
Timing Diagram
E 0.0: ____/‾‾\__/‾\______
T 1: ____/‾‾‾‾‾‾‾‾‾‾\___ (retrigger extends the pulse)
Code Example
U E 0.0
L KT 030.2 // 30 × 1s = 30 seconds
SE T 2
U T 2
= A 4.0 // ON for full 30 seconds, regardless of E 0.0
Typical Use
Signal lights, alarm outputs, minimum run times — anything that must stay on for a guaranteed minimum duration.
Related: SI (Pulse) — Non-extended version
Part of the S5 AWL Command Reference. Maintained by PLCcheck.ai.
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