Iec Timer Instructions - Siemens SIMATIC S7-200 System Manual

IEC Timer Instructions

On-Delay Timer
The On-Delay Timer (TON) instruction counts time when the
enabling input is on.
Off-Delay Timer
The Off-Delay Timer (TOF) delays turning an output off for a
fixed period of time after the input turns off.
Pulse Timer
The Pulse Timer (TP) generates pulses for a specific
duration.
Table 6-75 Valid Operands for the IEC Timer Instructions
Inputs/Outputs Data Types
Txx TON, TOF, TP Constant (T32 to T63, T96 to T255)
IN BOOL
PT INT
Q BOOL
ET INT
Tip
You cannot share the same timer numbers for TOF, TON, and TP. For example, you cannot
have both a TON T32 and a TOF T32.
The TON instruction counts time intervals up to the preset value when the enabling input
-
(IN) becomes true. When the elapsed time (ET) is equal to the Preset Time (PT), the timer
output bit (Q) turns on. The output bit resets when the enabling input turns off. When the
preset is reached, timing stops and the timer is disabled.
The TOF instruction delays setting an output to off for a fixed period of time after the input
-
turns off. It times up to the preset value when the enabling input (IN) turns off. When the
elapsed time (ET) is equal to the preset time (PT), the timer output bit (Q) turns off. When
the preset is reached, the timer output bit turns off and the elapsed time is maintained until
the enabling input makes the transition to on. If the enabling input sets the transition to off
for a period of time shorter than the preset time, the output bit remains on.
The TP instruction generates pulses for a specific duration. As the enabling input (IN) turns
-
on, the output bit (Q) turns on. The output bit remains on for the pulse specified within the
preset time (PT). When the elapsed time (ET) reaches preset (PT), the output bit turns off.
The elapsed time is maintained until the enabling input turns off. When the output bit turns
on, it remains on until the pulse time has elapsed.
Each count of the current value is a multiple of the time base. For example, a count of 50 on a
10-ms timer represents 500 ms. The IEC timers (TON, TOF, and TP) are available in three
resolutions. The resolution is determined by the timer number, as shown in Table 6-76.
Table 6-76 Resolution of the IEC Timers
Resolution
1 ms
10 ms
100 ms
Operands
I, Q, V, M, SM, S, T, C, L, Power Flow
IW, QW, VW, MW, SMW, SW, LW, AC, AIW, *VD, *LD, *AC, Constant
I, Q, V, M, SM, S, L
IW, QW, VW, MW, SMW, SW, LW, AC, AQW, *VD, *LD, *AC
Maximum Value
32.767 s (0.546 minutes)
327.67 s (5.46 minutes)
3276.7 s (54.6 minutes)
S7-200 Instruction Set
Timer Number
T32, T96
T33 to T36, T97 to T100
T37 to T63, T101 to T255
Chapter 6
201