STEP7 PLC Timers

Step7 Timers

English mnenonics	German mnenonics	Timer	Name	Diagram
SD	SE	S_ODT	On-Delay Timer
SF	SA	S_OFFDT	Off-Delay Timer
SP	SI	S_PULSE	Pulse Timer
SE	SV	S_PEXT	Extended Pulse Timer
SS	SS	S_ODTS	Retentive On-Delay Timer
FR	FR		Enable Timer (Free)
R	R		Reset Timer
L	L		Load Current Timer Value into ACCU 1 as Integer
LC	LC		Load Current Timer Value into ACCU 1 as BCD

Step7 Timer example for STL (AWL)

// Example STL Timer - English syntax

A	I 0.0	// Test input bit 0.0
L	S5T#10s	// Preset 10 seconds into ACCU 1.
SD	T1	// Start On-Delay Timer

A	T1	// Check signal state of timer T1.
=	Q 4.0	// Make output bit 4.0

// German syntax

U	E 0.0
L	S5T#10s
SE	T1

U	T1
=	A 4.0

Time Value — Human-readable time format

S5T#<hours>H <minutes>M <seconds>S <milliseconds>MS

• Minimum value: S5T#10MS

• Maximum value: S5T#2H46M30S

// Example - Human-readable time constants

L	S5T#10MS	// 10 ms (timebase = 10 ms)
L	S5T#5S		// 5 s (timebase = 10 ms)
L	S5T#1M20S	// 1 m, 20 s (timebase = 100 ms)
L	S5T#5M30S	// 5 m, 30 s (timebase = 1 s)
L	S5T#1H40M	// 1 h, 40 m (timebase = 10 s)

Time Value — Native time format

W#16#<resolution> <BCD>

• <Resolution> (1 decimal code number)

Code	Resolution or Time Base	Range of Time value
		min	max
0	0.01 s (10 ms)	10 ms	9s 990ms
1	0.1 s (100 ms)	100 ms	1m 39s 900ms
2	1 s	1 s	16m 39 s
3	10 s	10 s	2h 46m 30s

• <BCD> integer (3 decimal digits)

Integer from 001 to 999.

// Step 7 Example - Native time constants

// Resolution = 10 ms, range = [10ms; 9s990ms]
L	W#16#0001	// 10 ms
L	W#16#0002	// 20 ms
L	W#16#0500	// 5 s (5000 ms)
L	W#16#0999	// 9 s, 990 ms

// Resolution = 100 ms, range = [100ms; 1m39s900ms]
L	W#16#1001	// 100 ms
L	W#16#1002	// 200 ms
L	W#16#1010	// 1 s (1000 ms)
L	W#16#1050	// 5 s (5000 ms)
L	W#16#1999	// 1 m, 39 s, 900 ms (99900 ms)

// Resolution = 1 s, range = [1s; 16m39s]
L	W#16#2001	// 1 s
L	W#16#2002	// 2 s
L	W#16#2005	// 5 s
L	W#16#2060	// 1 m (60 s)
L	W#16#2999	// 16 m, 39 s (999 s)

// Resolution = 10 s, range = [10s; 2h46m30s]
L	W#16#3001	// 10 s
L	W#16#3002	// 20 s
L	W#16#3006	// 1 m (60 s)
L	W#16#3030	// 5 m (300 s)
L	W#16#3360	// 1 h (3600 s)
L	W#16#3999	// 2 h, 46 m, 30 s (9990 s)