Timer Instructions; Simatic Timer Instructions - Siemens Simatic S7-200 System Manual

S7-200 Programmable Controller System Manual

Timer Instructions

SIMATIC Timer Instructions

On-Delay Timer
Retentive On-Delay Timer
The On-Delay Timer (TON) and Retentive On-Delay Timer (TONR)
instructions count time when the enabling input is on. The timer
number (Txx) determines the resolution of the timer.
Off-Delay Timer
The Off-Delay Timer (TOF) is used to delay turning an output off for
a fixed period of time after the input turns off. The timer number
(Txx) determines the resolution of the timer.
6
Table 6-69
Inputs/Outputs Data Types
Txx
IN
PT
Tip
You cannot share the same timer number (Txx) for an off-delay timer (TOF) and an on-delay timer
(TON). For example, you cannot have both a TON T32 and a TOF T32.
As shown in Table 6-70, the three types of timers perform different types of timing tasks:
-
You can use a TON for timing a single interval.
-
You can use a TONR for accumulating a number of timed intervals.
-
You can use a TOF for extending time past an off (or false) condition, such as for cooling a motor
after it is turned off.
Table 6-70
Type
TON
TONR
TOF
1
The retentive timer current value can be selected for retention through a power cycle. See Chapter 4 for information about
memory retention for the S7-200 CPU.
Refer to the Tips and Tricks on the documentation CD for a sample program that uses the on-delay timer
(TON). See Tip 31
Tips and Tricks
196
Valid Operands for the SIMATIC Timer Instructions
Operands
WORD Constant (T0 to T255)
BOOL I, Q, V, M, SM, S, T, C, L, Power Flow
INT IW, QW, VW, MW, SMW, SW, T, C, LW, AC, AIW, *VD, *LD, *AC, Constant
Operations of the Timer Instructions
Current >= Preset State of the Enabling Input (IN)
Timer bit on ON: Current value counts time
Current continues counting
OFF: Timer bit off, current value = 0
to 32,767
Timer bit on ON: Current value counts time
Current continues counting
OFF: Timer bit and current value maintain last
to 32,767
state
Timer bit off ON: Timer bit on, current value = 0
Current = Preset, stops
OFF: Timer counts after on-to-off transition
counting
Power Cycle/First Scan
Timer bit off
Current value = 0
Timer bit off
Current value can be
1
maintained
Timer bit off
Current value = 0