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, and the resolution is now shown in the instruction box.
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, and the resolution is now shown in the instruction box.
Table 6-72 Valid Operands for the SIMATIC Timer Instructions
Inputs/Outputs
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 6-73, 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 6-73 Operations of the Timer Instructions
Type Current >= Preset
TON Timer bit on
Current continues counting
to 32,767
TONR Timer bit on
Current continues counting
to 32,767
TOF Timer bit off
Current = Preset, stops
counting
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.
196
Data Types 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
State of the Enabling Input (IN)
ON: Current value counts time
OFF: Timer bit off, current value = 0
ON: Current value counts time
OFF: Timer bit and current value
maintain last state
ON: Timer bit on, current value = 0
OFF: Timer counts after on-to-off
transition
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